Hi Elzee,
Prior to upgrading to 10.5, I used 10.4 with Safari 3.0b and I never had any issues. *However*, I had previously run NC and HC so it is possible that I didn't have to do an installation. I'm now using 10.5 with Safari 3 and it works well with SA 6.0+. I don't think it's officially supported though.
Have you tried using Firefox to do the initial contact and then using Safari 3.0? Just to see if once an installation is complete, it works OK.
Rgds,
Guy