Recently started using a Macbook Pro, formerly ran Firefox on a PC. Installed Acrobat and it works fine, and will download pdfs from internet fine, UNLESS it is from certain sites, that as near as I can tell have in common that I needed a password to get in (eg, Bank, insurance company). At this sites I can't download a pdf file, and am told that an "unknown error" occurred and I should try saving directly link to the disk. But this doesn't work either, it just wants to save a .cgi file, not the pdf. Any suggestions greatly appreciated.