Connector, C++, SQLBindParameter, SQL_C_WCHAR Not Working?

[garbage]

I've created a table with a varchar(255) field with the default  
character set.  I'm using Windows for the server and application  
development with ODBC.  I am doing something like:

std::wstring SqlStatement = L"SELECT * FROM blah WHERE blahField LIKE ?";
SQLPrepare(....)
SQLBindParameter(hstmnt, 1, SQL_PARAM_INPUT, SQL_C_WCHAR, SQL_WCHAR,  
255, 0, const_cast<LPWSTR>(L"TestStr"), 7, 0);
SQLExecute(hstmnt);
SQLFetchNext(hstmnt);

I end up getting SQL_NO_DATA returned even though I can use the MySQL  
command line client to do a select and see that said row exists.  I've  
tried SQL_WCHAR, SQL_CHAR, SQL_VARCHAR, SQL_WVARCHAR for that 5th  
parameter, and none of them work.  But if I use SQL_C_CHAR, SQL_CHAR,  
and "TestStr" (no wide charaters), it works just fine.

Any help?

Connector and Server are 5.1 community editions.

Thanks,

Torin Ford