SQL Code crashing my game :(

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C++

SQL

ODBC

I'm coding a game. (MMORPG) private server.
and when I load with command the infomartion of the player (From SQL)
Its works perfect.
But if I typing worng name. that's the SQL not found at the SQL.
Its crashing my game. (The server side)
And I just want its say "Error" and wor'nt crsash it ..

Sorry for my bad english ..
and here the code ..

std::string CQuery::CheckName(int aIndex, char *Name)
{
	char String[256];
	char Query[150];
	SQLCHAR Str[5][64];
	SQLINTEGER Indicator[5];
	SQLSMALLINT Col;
	SQLRETURN Retcode;
	Clear();
	wsprintf(Query, "SELECT Name FROM Character WHERE Name = '%s'", Name);
	Retcode = SQLExecDirect(hStmt, (SQLCHAR*)Query, SQL_NTS);
	SQLTables(hStmt, NULL, 0, NULL, 0, NULL, 0, (SQLCHAR*)"TABLE", SQL_NTS);
	SQLNumResultCols(hStmt, &Col);

	for(int i = 0; i < Col; i++)
	{
		SQLBindCol(hStmt, i + 1, SQL_C_CHAR, Str[i], sizeof(Str[i]), &Indicator[i]);
	}
	while(SQL_SUCCEEDED(SQLFetch(hStmt)))
	{
		for(int i = 0; i < Col; i++)
		{
			if(Indicator[i] != SQL_NULL_DATA)
			{
				wsprintf(String, "%s", Str[i]);
				if(strcmpi(String, Name) == 0)
				{
					return String;
				}
				else
				{
					GCServerMsgStringSend("ERROR", aIndex, 1);
				}
			}
		}
	}
}

Any idea ?
(Btw the game is: Mu Online :D )