libpthread not found

[m.borsatino at alice.it]

Hi.
I've installed netbeans from ports without error messages. when I started the program I got an error like this: "libpthread.so.2 needed by java not found". I've verified that there is a libpthread.so.20 in /usr/local/lib/pth. I've done a rough attempt making a soft link; after that I've restarted netbeans; now the error message is: "/libexec/ld-elf.so.1: Shared object "libc.so.6" not found, required by "java", also present but with version libc.so.7.
the same think happen with netbeans 6.1 and with netbeans 6.4 either installed from ports or packages and also using a binaries. 
have I done a mistake? how can I fix it?
thanks for any idea.
Marco.