OS 10.4 - Mail leading problems

The leading is messed up on the "from", "subject", "date" and "to" lines that appear at the top of an email message. The sender's name appears first, followed by about 15 blank lines, then the word "from". The subject line appears next, then the date. Then on the last line is my name (recipient). Then, about 15 blanks lines, and finally the word "to". Ordinarily, all four lines should be stacked neatly on top of each other, as a header to the main email message. What's up? I tried deleting the mail preference file, but that didn't help. G4 iMac, Tiger, Mail 2.0.5. :mail: