I think you found the problem :-)

Should take no more than a simple 3.5mm mono mini-jack. If you buy one at Radio Shack, ask 'em if they have one that does not need any soldering (sp?), unless you are equipped to do that.

As an alternative, you could buy a new IR-emitter for less than $10, from many places (e.g. www.smarthome.com or www.xantech.com).