pg_lo_read_all problems

Hi, I'm writing because I'm having trouble with the pg_lo_read_all function in PHP. Specifically, on my Mac OS X (latest stable PHP for Mac OS X) when I try to download a file with pg_lo_read_all it downloads fine but a few bits are different. I know this because the cmp(1) command tells me that the first line has changed. I'm sending headers first to set file type (Content-disposition) and file name (content-type I think). Any other experience with this problem? Can someone tell me if this works on another platform? Thanks! Justin