I've had a problem like this before. Steps that worked for me were:
1. Make that mime type addition and restart webserver 2. Clear file cache in the browser that downloaded the .jnlp file (it will still have a copy with the mine type set as text/html) 3. Try downloading again.
Hope that works for you.
SCJP 1.4 91%, SCJP 1.5 88%, SCJD B&S
Joined: Aug 11, 2003
Thanks Jared. Now it works fine.
subject: JNLP Error: Bad MIME type returned from server when accessing resource: