Try clicking on file > disconnect, then file > connect.

What version of Java are you using? Lots of people have had problems with 1.6.0_01 so if that's the version you have...try this one instead.
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11

Use the JRE offline installer & remove your current Java version before you install this other one

If that doesn't help, please give us your details.
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