Thanks for your information Kavan! Just to try it, I installed the new version of the gnu-compiler and it compiled. Unfortunately, I can not use it really, because we deliver binaries (from f77+C) for RH 6.2, which rules out any changes in the libraries. But everything (almost) worked fine after installation of Daniels libstdc version.
And on my old Laptop with Mandrake 7.0, everything worked without any changes. The distributed library was already correct! Joachim