Power2go(5.5) weirdness

Ok whenever I try to burn a large file 4.37 gigs to be exact power2go says that the file exceeds the disc size…yes I changed the file system from iso966o/joliet to udf…it appears to be adding some sort of extra data which then exceeds the disc size? I can burn the same file using Vistas burn interface but thats is limited to 6x for some reason (18x burner) or I can create an img with img burn and that works as well so its not the file or the discs…any idea as to whats going on??