Mail zips attachements

hi, hope someone can help with this.

My wife has a white G3 iBook 700 that I recently installed Tiger on. Now, when she uses Mail to send attachments, such as 2 Word documents, the person on the other end gets them zipped with about 6 or 7 other weird files that she never sent. To attach files, she just clicks on the "Attach" button and adds the two files separately.

The weird thing is, I have Tiger installed on my 12" PB 1Ghz, and if I do the exact same thing, they arrive at their destination completely unharmed, unzipped, no new files added, etc.

Incidentally, we're sending Word files to the same person, who uses a PC, and neither of us checks the "Send Windows-friendly file attachments" option.

Can anyone help me get her computer to stop doing this? She of course blames me for the problem since I'm the one that installed Tiger (it worked fine with Jaguar for her).

thanks,
bb