hmmmm not sure how a .bmp got into your posts if your not allowing them... go to my test site and try to upload a picture that's not a .gif or .jpg and over 100k in size... it was not letting me do it but maybe that was just me. I'm using the exact same code in the 1.5.1 text file I have posted in the file attachments area.
Let me know how it goes... I don't think I have any errors but it's not like that don't ever happen... lol