There have been several differant releases of this game. Each using a differant set of level codes. Try the codes below to hopefully find the ones that work with your release version.
0- "LQPONTQNJO"
1- "LQPONRHCNM"
2- "LQPONUPQCK"
3- "LQPONTMBCH"
4- "HQPOOOCENT"
0- "LQPONTQNJO" or "LQPONSSFRP"
1- "LQPONRHCNM"
2- "LQPONUPQCK"
3- "LQPONTMBCH"
4- "HQPOPONLRK"
5- "PQPOQTETNT"
Some others to try:
"LQPONTCONF" | "HQPOOTCMJM" | "PQPOPGSPRT"