Imap_base64/imap_8bit

I have a question. I seem to easily make these functions GPF (under windows obviously) this occurs when I try and attach HTML as a quoted-printable text to an Email. I have a mime Email class which I did a couple of alterations too coz it had some serious bugs, but, before you ask, it depends on the HTML. I havent worked out quite yet what does it, but it partly seems to be size, and partly content, I can work out some code to reproduce this, but its not that small, as, after all, size is partly the problem. Anyone here actually use these functions to do a similar job and have it working?