throw in a debug.print sql the SQL generation line and see what it's giving you, cut and paste that code to the SQL window of a query in Access and see what happens, you'll likely get a better (more usable) error message than in your vb code.
Code:
SQL = "SELECT [" & DistributionLists & "] as Fld FROM " & DistroLists & " WHERE " & string1 & "=" & Application
debug.print sql
I suspect it's something to do with your 'Application' unless that's a field on your form, application may be a reserved word and that's why you may be having trouble with it. Try changing your field name to fldApplication and your SQL statement to
Code:
SQL = "SELECT [" & DistributionLists & "] as Fld FROM " & DistroLists & " WHERE " & string1 & "=" & fldApplication