Same problem here but in a Rule containing an accumulate:<div><br></div><div><span class="Apple-style-span" style="font-family: monospace; font-size: 11px; color: rgb(51, 51, 51); "><ol><li class="li1" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial; ">

<div class="de1" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">rule &quot;fromAccumulateRule&quot;</div></li><li class="li2" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(248, 248, 248); background-position: initial initial; background-repeat: initial initial; ">

<div class="de2" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">        dialect &quot;mvel&quot;</div></li><li class="li1" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial; ">

<div class="de1" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">        when</div></li><li class="li2" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(248, 248, 248); background-position: initial initial; background-repeat: initial initial; ">

<div class="de2" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">                fc : Car( ) from accumulate ( Car( b : brand)</div></li><li class="li1" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial; ">

<div class="de1" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">                        init( Car c= new Car(); ),</div></li><li class="li2" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(248, 248, 248); background-position: initial initial; background-repeat: initial initial; ">

<div class="de2" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">                        action( c.brand = c.brand + b; ),</div></li><li class="li1" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial; ">

<div class="de1" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">                        result( c )</div></li><li class="li2" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(248, 248, 248); background-position: initial initial; background-repeat: initial initial; ">

<div class="de2" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">)</div></li><li class="li1" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial; ">

<div class="de1" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">        then</div></li><li class="li2" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(248, 248, 248); background-position: initial initial; background-repeat: initial initial; ">

<div class="de2" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">                insert (fc);</div></li><li class="li1" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial; ">

<div class="de1" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">end</div><div class="de1" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; "><br></div>

<div class="de1" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; "><br></div></li></ol></span></div><div>The error is the same:</div><div><br></div><div><span class="Apple-style-span" style="font-family: monospace; font-size: 11px; color: rgb(51, 51, 51); "><ol>

<li class="li1" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); background-position: initial initial; background-repeat: initial initial; ">

<div class="de1" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">Caused by: org.drools.RuntimeDroolsException: [Error: unable to access property (null parent): b]</div></li><li class="li2" style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(248, 248, 248); background-position: initial initial; background-repeat: initial initial; ">

<div class="de2" style="font-family: &#39;Courier New&#39;, Courier, monospace; font-weight: normal; ">[Near : {... Unknown ....}]</div></li></ol></span><div>A full stacktrace is available here: <a href="http://drools.pastebin.com/f1638db0e">http://drools.pastebin.com/f1638db0e</a></div>

<div><br></div><div><br></div><div>Best,</div><br><div class="gmail_quote">On Tue, Jan 26, 2010 at 10:24 PM, Barry Kaplan <span dir="ltr">&lt;<a href="mailto:groups1@memelet.com">groups1@memelet.com</a>&gt;</span> wrote:<br>

<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><br>
Ok, I see from previous posts that we are having mvel issues. Cool.<br>
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