When I run \"clean and build\" the .jar file that is being created only runs if the lib folder is at the same folder of the .jar file.
This is what worked for me:
I built in excel export functionality into my project. The 2 external .jars I used for this purpose was jxl.jar end sx.jar
Unpack these 2 jars into a folder(java classes) using 7-Zip without any META files. Unpack your project jar into the same folder including the META file.
Re-Pack the whole java classes folder using JARMaker to recreate your Project .jar in its original distribution folder ... and there you go ... full excel functionality.