[Serusers] MySQL support faild - Ser can'r connect to Database - Why?

Hello Friends, I have installed Ser with MySQl support and Serweb.Wenn I start the Ser in normal mode - all things are ok and the Ser don't make any failure. Whenn I turned the fork mode on , and start the Ser a second time, it show me a connection error with mysql. Ser can't connect to Database ,so that i can not register any Users with Serweb or so . But serctl work's fine. The database name and password was ser and heslo. I'm using Ser Verison 08-09 but ist still the same failure and i doesn't now, how i can make it better. I'm using the standard ser.cfg file with the normaly changes of IP-Adresse and db_mode. I hope anyone can help me with this problem. I only want to setup a Ser with Mysql Support and Serweb. Thanks and greetings, Dirk