Overflow error in database?

hi,

I am executing an INSERT SQL statement on the database.
The execute function is leaving with System Error(-9). 
This is Overflow error. can anyone explain this error in database context.

Gaurav Jain

/// Code:

RDbs dbSession;
User::LeaveIfError( dbSession.Connect() );
CleanupClosePushL( dbSession );
RDbNamedDatabase database;
User::LeaveIfError( database.Open( dbSession, KDatabaseName) );
CleanupClosePushL( database );

_LIT(KSQLSelect, "INSERT INTO ");

TBuf<240>  SQLStatement;  // define KMaxSQLStatementLength 256
SQLStatement = KSQLSelect;
SQLStatement.Append( _L("Table1") );  // Append name
SQLStatement.Append(_L(" (field1, field2) VALUES ('"));
SQLStatement.Append(funcX());
SQLStatement.Append(_L("','"));
SQLStatement.Append(funcY());
SQLStatement.Append(_L("')"));
User::LeaveIfError(database.Execute(SQLStatement));

database.Close();
dbSession.Close();
CleanupStack::PopAndDestroy(); // database
CleanupStack::PopAndDestroy(); // dbSession