Install.sh doesn't start at all on Linux!

Hi,
I'm trying to install :
Product=IBM WebSphere Portal Express 5.0.2.3
Version=5.0.2.3
Build=20050412_1242

the setup doesn't want to start, I tried everything, and all the tip from this interesting url <http://www.nsftools.com/tips/WSPXInstall.htm>, but I'm too down now! :(

I have attached the log file, it seems to be java the problem, but I have tried all version possible from IBM 1.3.x, I must confess that I don't know what it is missing.

Thanks to all!

error while loading shared libraries: libpthread.so.0: cannot open shared object file: No such file or directory

This is the error...

Thanks!