Well it's normally a 34 pin format, but can have one of the corner pins missing and one of the middle pins missing.
It is possible that you are trying to use the wrong cable, or the wrong header. IDE cables are 40 pins and will not work with a floppy drive. (Okay I'm 1337 so I could get one to work, but I don't feel like typing 2 or 3 pages to explain how and why) There are often headers on motherboards for alternate front panel connectors, for modem risers, or other feature connectors (audio, video etc etc) that look like a floppy port, but aren't.
Another possibility is that you have an LS120 A: drive, which is an IDE device not a floppy controller device and therefore will have a 40 pin IDE interface.
regards,
Road Warrior