[X4U] jar launcher pb

[x4u at listserver.themacintoshguy.com]

Hi,

when I 2click on any xxx.jar file I get an error message saying
"The jar file 'xxx.jar' couldn't be launched. Check the Console for
possible error message".

Trying the cl here is what I get:
"MEs-Computer:/Applications me$ java -jar mac.jar
Failed to load Main-Class manifest attribute from
mac.jar"

My setup: 20' iMac Core 2 Duo, Tiger 10, J2SE 5.0

Thanks for any help. BTW have sent this to several other lists, to no
avail. Even a respected MacWorld guru
claims to ignore Java too much in order to give a solution.

-- 
Michel Eytan
           eytan at umb.u-strasbg.fr
                                                                    I
say what I mean and mean what I say