After downloading 5.1 binaries from
http://www.jboss.org/drools/downloads.html
and unzipping them in a fresh, new directory I find:
wlaun@atvienw39033:/extra/drools-5.1/bin$ ls -l
total 14316
-rw-r--r-- 1 wlaun wlaun 116205 2010-08-04 13:44 antlr-runtime.jar
-rw-rw-r-- 1 wlaun wlaun 12866 2010-07-30 10:22 drools-ant-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 156008 2010-07-30 10:22 drools-api-5.1.0.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-r--r-- 1 wlaun wlaun 127191 2010-08-04 13:44 drools-api.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-rw-r-- 1 wlaun wlaun 16589 2010-07-30 10:22 drools-bam-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 266804 2010-07-30 10:22 drools-bpmn2-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 38093 2010-07-30 10:22 drools-camel-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 84894 2010-07-30 10:22 drools-clips-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 1119468 2010-07-30 10:22 drools-compiler-5.1.0.jar
<<<<<<<<<<<<<<<<<<<<
-rw-r--r-- 1 wlaun wlaun 1159712 2010-08-04 13:44
drools-compiler.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-rw-r-- 1 wlaun wlaun 2103665 2010-07-30 10:22 drools-core-5.1.0.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-r--r-- 1 wlaun wlaun 1776713 2010-08-04 13:44
drools-core.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-rw-r-- 1 wlaun wlaun 49926 2010-07-30 10:22
drools-decisiontables-5.1.0.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-r--r-- 1 wlaun wlaun 47227 2010-08-04 13:44
drools-decisiontables.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-rw-r-- 1 wlaun wlaun 8992 2010-07-30 10:22 drools-doc-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 61872 2010-07-30 10:22 drools-grid-core-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 30056 2010-07-30 10:22 drools-jsr94-5.1.0.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-r--r-- 1 wlaun wlaun 30110 2010-08-04 13:44 drools-jsr94.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-rw-r-- 1 wlaun wlaun 60520 2010-07-30 10:22
drools-persistence-jpa-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 199641 2010-07-30 10:22
drools-process-task-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 13949 2010-07-30 10:22 drools-simulator-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 46808 2010-07-30 10:22 drools-spring-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 53291 2010-07-30 10:22
drools-templates-5.1.0.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-r--r-- 1 wlaun wlaun 46160 2010-08-04 13:44 drools-templates.jar
<<<<<<<<<<<<<<<<<<<<<
-rw-rw-r-- 1 wlaun wlaun 192069 2010-07-30 10:22 drools-verifier-5.1.0.jar
-rw-rw-r-- 1 wlaun wlaun 35248 2010-07-30 10:22 drools-workitems-5.1.0.jar
-rw-r--r-- 1 wlaun wlaun 534827 2010-08-04 13:44 joda-time.jar
-rw-r--r-- 1 wlaun wlaun 13749 2010-08-04 13:44 jsr94.jar
-rw-r--r-- 1 wlaun wlaun 499068 2010-08-04 13:44 jxl.jar
drwxrwxr-x 2 wlaun wlaun 4096 2010-07-30 10:22 lib
-rw-rw-r-- 1 wlaun wlaun 11358 2010-07-30 10:22 LICENSE-ASL-2.0.txt
-rw-r--r-- 1 wlaun wlaun 607526 2010-08-04 13:44 mvel2.jar
-rw-r--r-- 1 wlaun wlaun 4372548 2010-08-04 13:44
org.eclipse.jdt.core_3.4.4.v_894_R34x.jar
-rw-rw-r-- 1 wlaun wlaun 3084 2010-07-30 10:22 README_DEPENDENCIES.txt
-rw-r--r-- 1 wlaun wlaun 119888 2010-08-04 13:44 xpp3.jar
-rw-r--r-- 1 wlaun wlaun 24956 2010-08-04 13:44 xpp3_min.jar
-rw-r--r-- 1 wlaun wlaun 431406 2010-08-04 13:44 xstream.jar
Please s.o. look into this.
-W