are you sure you are showing the right macro? error in your first image is about opening a database, whilst macro is about opening a form. And the error code shown there (3197) is
"Run-Time Error '3197' The Microsoft Access database engine stopped the process because you and another user are attempting to change the same data at the same time."
I've also heard but not confirmed that the 3197 error can occur with a corrupted memo/long text field or OLE object and since multi value fields operate on the same principle probably those as well (These are all stored in separate hidden tables from the 'main table'). So it may be a specific record or two are causing the issue. Does the form you are opening have any of these features?
I don't use macros so can't help with that but
1. is the error repeatable - i.e. if you run you macro a second time does it work ok? or run it with different parameters does it fail or work?
2. can you open the table/query used by the form you are opening from the navigation window without a problem? In particular for the records that are called by your macro openform
3. ditto for the form you are opening
4. although you are using macros, probably worth decompiling as well - see this link how to do it
http://www.fmsinc.com/microsoftaccess/performance/decompile.asp
5. have you compact/repaired? if not, take a copy and compact repair that and see if it solves the problem