when I try to install Midlets on a 7650 (real device) I get the error message
"Application WmlBrowser USER 21"
The Midlets are downloaded properly but the installation seems to fail. Apache is configured OK and some other Midlets do work. Just the ones I compiled don't work. I tried with J2MEWTK103, Forte4J_ME and Java 1.4.0 on W2K. All Midlets work fine in the Emulator (even tried the simplest HelloWorld Midlet...)!
I have had similar problem..
When problem occured I had to delete all push messages and uninstall previous version of the program. Then reboot the phone (battery off and wait few seconds..) -> phone on and new push and installation worked..