Need a little java help

when i try to upload games or apps to my phone (motorola l6) i get this problem.
I get through everything good i have java app enabled on phone i use midway to get the game loaded but when i go to move the game and or app to my phone my phone says "not a signed application. continue downloading?"i click yes and then i get

Opening JAD file.............[OK]
Connecting the phone.........[OK]
Transmitting data blocks.....[OK]
Completing transmission......[OK]

Opening JAR file.............[FAILED]

JAR downloading failed.

anyone know what is going on. im kinda new to this so i could use a little help.

thanx, hunter