Error message in upsell page

[cdelarte]

I get the following error message if add an upsell item on the upsell page (UATM) and click "continue":

If I do not select item, I do not get the error. Any suggestions:

Fatal Error
MIVA Merchant has encountered a fatal error and is unable to continue. The following information may assist you in determining the cause of the error:

Error Code: MER-00001 Description: <b>Unknown Error</b><br><br>&nbsp;&nbsp;Action = AUPM<br>&nbsp;&nbsp;Screen = OSEL Other Information:

[Red Flare]

I think its a known bug, look in the bug thread.