I created a project in Windows Movie Maker (photo slide show with music) I played it back in windows movie maker, was delighted with the result and saved it to my computer but when I try to burn it to DVD I get the message bad parameter passed in can you help please. I have made similar DVDs without any trouble

The error message is probably only valuable to the programmer who wrote the program. It appears that somehow you have managed to create something that is incompatible with the program, itself. About the only way you'll be able to fix this is to re-create the project (a lot of work, I'm sure) or talk to Microsoft (even if they would talk to you, which they probably won't, they would still take forever to get a fix so this won't work, either).

It might be possible to make some changes to the project and get it to burn to a CD/DVD. What changes those could be, can only be guessed.