Here is the VB code that finally worked:
...

Thank you for the feedback, Stewart. I wrote the code that way because I was instructed by other resources to use that format. Writing the code as you have indicated did not fix the problem. I didn't get another error message, but nothing happened at all once I selected CustomerName.

I adjusted the formatting of fields and VB code as follows and now it returns a value for ProductID, but not the one associated with the specified CustomerName:...

Hello all.

I am trying to use DLookup to auto-populate fields in an otherwise simple database. I am using Access 2010. I have created three different databases and the code still does not work. I think there may be glitches in this particular copy of the program. Please evaluate the details below and tell me what you think.

Table 1 has fields: Product ID, CustomerName, CustomerAddr, and ComplaintLevel.

Table...