为什么我在jnlp中得到UnsupportedClassVersionError？

I get an UnsupportedClassVersionError thrown when launching jnlp, however when I try to run the relevant jar files from command line everything works fine. I tried setting j2se versions to 1.5+, 1.6+, using signed/unsigned jar files, but all that doesn't help.I get an UnsupportedClassVersionError thrown wh