Mailmerge Database Access read write issue on migrating to 64bit W7

Running an automated mailmerge VBA process I get a

"The Microsoft Access database engine cannot open or write to the file ''. It is already opened exclusively by another user, or you need permission to view and write its data"

Error.

The mailmerge between Excel & Word sends 100's of word mail files as attachments to email addresses using outlook, all the code is in a VBA script in the source excel file. This worked fine in XP & office 2010 (32 bit), but now since switching to W7E 64bit SP1 & Office 2010 it gets about 25% of the way through the exercise (so sends some fine) but then falls over.