[rules-users] Unable to validate package configuration (eg, DSLs, models) for [package name]

Hi, We recently upgraded from Drools/Guvnor 5.0.1 to 5.1.1 (early December). We had an existing package we had developed in 5.0.1 that we had not done much with since the upgrade. This morning, we tried to open one of the rules in that package and we get the following messages: <<Picture (Device Independent Bitmap)>> Unable to validate package configuration (eg, DSLs, models) for [package name]. Suggestion completions may not operate correctly for graphical editors for this package. <<Picture (Device Independent Bitmap)>> Unable to get content assistance for this rule. <<Picture (Device Independent Bitmap)>> Unable to get content assistance for this rule. I've tried to re-upload the 3 jar files (I saw this post as a possible solution: http://comments.gmane.org/gmane.comp.java.drools.user/23407), but I get "Unable to upload the file". New packages seem to be okay (e.g. packages created since the upgrade). Does anyone have any thoughts on what's going on here? Thanks.