While I agree with everyone about the ease of transferring everything over from a PC, I cannot recommend Thunderbird. A friend uses it, and it has some seriously strange behaviors...much like the ones at the Another Subcontinent forum that keeps me from using it. (Slow-moving, slow-appearing characters,
i suggested thunderbird only as a transfer vehicle. it can import outlook mail in windows and since a mac version exists of it the files can be transferred easily.
as for your mysterious troubles with another subcontinent's forums no one else seems to be able to replicate them. perhaps it is a mac/safari version thing with invision (and/or the forum mods in use there).