Hi and thank you for your reply.
I'm installing through Software Updates -> adding new Site -> the URL: http://dl.google.com/eclipse/inst/codepro/latest/3.4
since the IBM RAD 7.5 is based on 3.4 (correct me if I'm wrong..).
After selecting all the CodePro's components, and Next -> Next -> .. I'm getting the error.
One other thing noticed:
the installation works perfectly on newly installation of RAD on a machine connected directly to Internet.
My problem is on a machine connected to Internet through an Proxy and with many other plugins installed (ClearCase, etc..)
Thanks for any ideas...