I'm seeing something like this, too -- a paste into TextMate loses all newlines and winds up as one long line. However, I think I'm only noticing it when I paste from Firefox.
So, here's a repeatable example:
* Open Firefox to http://instiki.org/ * Click "Edit Page" at the bottom. * Select all in the editable textarea. * Paste into a TextMate window
... you should see that all the newlines have disappeared.
I haven't been able to make this paste problem happen yet copying from anything except Firefox.
Interestingly, if you save the TextMate buffer to a file (leaving it as is, with the newlines gone), then close the window and re-open it in TextMate ... the newlines have been preserved in the underlying file and now show up.
I hope that helps, I assume the original poster is seeing something along these lines and that this is not a separate but related issue.