QuartusII 11.1 on Fedora15 : Internet Connectivity with FireFox

I've moved from Windows to Fedora15, installed QuartusII 11.1 Web Edition. After installation, I could not access to online resources (e.g., HELP) even though I set FireFox (version 8) to Internet Connectivity setting.

Error message (on terminal from which QuartusII gets launched) says:

/home/***/altera/11.1/quartus/linux/libstdc++.so.6: version 'LIBCXX_3.4.15' not found.....

As quick fix, I copied /usr/lib/libstdc++.so.6 to /altera/11.1/quartus/linux directory, and on-line help with FireFox 8 started working fine.

This is a piece of information for those who would be in similar situation.

If there is better solution than this 'simple file copy/overwrite', I'd appreciate have your advice.