"The HotSync operation was interrupted. Some of your data was NOT backed up."?

Well I have a Zire 72s Palm One Handheld PDA. I have added songs in the past to the device, but for some reason now when I try to do it, it gives me the message stated in the question. And when I check the log it says "HotSync Error: An application cancelled sychronization or failed to respond to a HotSync notification. Please ensure that you are not currently editing data using applications such as Palm OS Desktop or Install Tool. (8009)" and I honestly have no idea why it's doing that. Could someone possible help me, please?