A user e-mailed me about his web site, built using ASP and Microsoft Access, that crashes when too many users hit the site. Some of the pages are just doing selections, but others are doing database changes. The basic problem with this architecture is that Access can only handle a limited number of simultaneous changes. It does fairly well when it's only handling selects, but when you start making lots of changes to the database, it can run into problems.
In addition, there are bugs with the OLE DB provider used for accessing Access 97 databases. If you use the OLE DB 4.0 provider with a Access 97 database, it can run into problems that cause the system to crash or hangup. The best idea is to upgrade the database to Access 2000 before using the OLE DB 4.0 provider. If you don't want to do that, use the OLE DB 3.51 provider with Access 97 databases.
Finally, the best architecture for a busy site that uses a database is to replace Access with SQL Server or another database that can better handle higher levels of traffic. Access does ok, but it's just not designed for high traffic applications.