Was it recorded as CD-Audio?
If you recorded MP3 files as "CD-Audio", the recording program would have de-compressed and converted the MP3s to standard audio files. That would play back in any CD player, but would have the same 74 to 80 minute limitation as regular CDs.
Recording MP3 files as "MP3 CD" or "Data CD" disks leaves the files compressed, allowing several hours of music to be stored on one disc. However, only some newer CD players that can read MP3s can play them. Since the ability to read MP3s is a great gimmick, CD players that support MP3 usually put a label bragging about it on the front.
DVD discs have much narrower tracks to pack more information on the disks, approx. 7 times more than a CD. The result is DVD players can easily read CDs, but a CD player cannot read DVDs.