With due respect....

Access can't take as many concurrent users as you like (unless you don't like many users). The official max. number of concurrent users is 255. Of the record Microsoft says that with more than 15 concurrent users doing update requests unpredictable results may occur (using the JetEngine, I should have mentioned that).

I was just wandering if many users just READING the database through Jet will cause problems.

I quote:

While Microsoft Jet is consciously (and continually) updated with many quality, functional, and performance improvements, it was not intended (or architected) for the high-stress performance required by 24x7 scenarios, ACID transactions, or unlimited users, that is, scenarios where there has to be absolute data integrity or very high concurrency.

My experience is that with about 20 users you won't have any problems provided you compress the database often (twice a week or so). Otherwise you will run into Corrupt database or Unrecognized database format messages.