My myibidder web based software no longer functions properly. I can not change the bid price already existing for an ebay item. It wrongly gives me an error message that a new item number is incorrect. I sent my confirmation email that I purchased your software with the key Monday, December 12, 2011

I think you opened a support ticket for this question already.
There is no really need to ask the same question in different places.

The Web based interface does not give such error message, this is probably the Windows application you are asking about.
I think your issue was regarding your connection being lost, so a simple restart should help.