windows 7 64 bit prob maybe

First off, Click Start then click on Control Panel



Then click on System and Maintenance (Or something similar)



Then click on System (Or once again something similar)



Then click on Advanced system settings (Or somthing similar..)



Then look for Environment Variables...



Then look under System variables and look for CLASSPATH, Click it and then press Edit...



Then you should have something that looks like this



Then change your Variable value to
.;C:\Program Files\Java\jre6\lib\ext\QTJava.zip
For 32-bit users
Or
.;C:\Program Files (x86)\Java\jre6\lib\ext\QTJava.zip
For 64-bit users

Then Press
Now you are done setting your CLASSPATH.
Please post if you have any Questions or if I helped you.
-Thanks