I have similar problem fairly frequently, since our network guys are always changing/upgrading pc's with little regard for my app's.
I run this code on the PC where everything works okay, write down the references, and then run the code on the pc that is misbehaving.
I usually find a missing reference that I have to restore:
Dim strMessage As String
Dim strTitle As String
Dim refItem As Reference
On Error Resume Next
For Each refItem In References
If refItem.IsBroken Then
strMessage = "Missing Reference:" & vbCrLf & refItem.FullPath
strMessage = "Reference: " & refItem.Name & vbCrLf _
& "Location: " & refItem.FullPath & vbCrLf
Inspiration Through Fermentation