Microsoft Access prepared statement with parameters problem

Hi there, I'm attempting to execute prepared statements with parameters against an Access 97 database, and am having some trouble. I'm sure I'm missing something really obvious, but I just can't see it, and I'm hoping someone out there can help. In the following code, assume that $connection holds a valid and otherwise working connection to a database in which there exists a table named System. Column A is a text column. $statement = odbc_prepare( $connection, "select * from System where A=?" ); if( odbc_execute( $statement, array( "MachineID" ))) { odbc_fetch_row( $statement ); print odbc_result( $statement, "A" ) . "<br/>"; } I have tried many variations on this code, and if there are any ? marks in the query, regardless what I pass as the second parameter to odbc_execute(), odbc_execute() always dies with the following message: Warning: SQL error: [Microsoft][ODBC Microsoft Access Driver]COUNT field incorrect , SQL state 07001 in SQLExecute in ... Can anyone tell me what I'm doing wrong? Thanks, Chris.