I got this little tidbit while in a chat with Kirk McElhearn (author of the upcoming book "Unix for Mac OS X: Learning the Command Line"). I was having some trouble pasting an image to Kirk (getting the dreaded "Rend Error" each time). He suggested pressing the space bar before before pasting the image. Amazingly enough, it worked.
Not just that one time, but most of my image pasting issues have vanished just by prefacing the pasted image with the space bar. I'll still get the very occasional error, but nothing near what I used to get -- thanks Kirk!
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030710223342613