I went in and manually edited the include_path in the php.ini file to include what you listed above, but am getting the same error.
Assuming I am running PHP as an Apache module (not sure, is there a way to check?) is there a workaround for that as well?
I just purchased XF and set about to installing it on my server but ran into a problem. When I went to the site.com/install/ directory where all the files were located it said I needed iconv to be active to use the software.
Probably my bad for not reading/running the requirements test script...