I’ve seen this happen when the RGE files were created on the Windows PC and then moved to the Mac. There are certain methods of moving files between Mac and PC that can screw up the encoding of the linefeed character.
Try this method instead:
1) copy your PST files to your Mac
2) run Emailchemy and convert Outlook PST to Entourage Archive (.rge files)
3) run Entourage and use its import wizard and import the .rge file you created in step 2