HTC Touch Diamond outlook sync woes

[Guest Delta caller]

I have a HTC touch diamond this phone is paired with 2 pc's Active sync. the problem is is that i keep getting an error message reporting

that cannot sync with an appoinment in July 2006.

I have deleted this appointment from both pc's and the phone manually.

I have also tried deleting the sync with both pcs, and then re sync with both pcs again.

I still get the error message on Active sync about cannot sync with appointment in July 2006, yet it doesn't exist on any device. it is reporting that the so called ghost appointment is on the phone. a) is there anyway of destroying this appointment or,

<_< how do i effectivly format outlook on the phone to start again.

thanks.