Bitness in Access isn't my forte, but I do know that the bitness of Windows is irrelevant to the situation. What matters is the bitness of Office and Access but you didn't say which you were referring to - those, or Windows. If your database is an accde or mde, Access bitness matters. If it's a mdb or accdb it's not supposed to matter but often does because of API calls.
You should check the code project in the db that presents the problems to see if there are any missing or broken references.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.