RE: SQL file not hardcoded

I just tried this:

ActSQL = 'Select Coalesce(Min(INVDT),' + @Q + '0001-01-01' + @Q + ')' +
', Coalesce(Max(INVDT),' + @Q + '0001-01-01' + @Q + ')' +
', Coalesce(Count(*),0) ' +
'Into ?, ?, ? From ' + uSlsFil;

Exec SQL Prepare Stmt1 from :ActSQL;

Exec SQL Execute Stmt1
Using :BgnDat, :EndDat, :TotRecs;

And it doesn't work. The joblog has:

Token ? was not valid. Valid tokens: : <IDENTIFIER>.

Followed by:

Prepared statement STMT1 not found.

I found the following in the SQL reference:

Reference and execution rules: Prepared statements can be referred to in the
following kinds of statements, with the following restrictions shown:

Statement The prepared statement restrictions
DESCRIBE None
DECLARE CURSOR Must be SELECT when the cursor is opened
EXECUTE Must not be SELECT

Note the restriction on EXECUTE. Does this mean I'm toast here?