dynamic wml using asp(wml encoding failed)

when i run my asp program on the nokia simulator brower,it the error message appear(can't load 'filename'HHTP server error).when i check the nokia gateway program to view the error,the error message appear(wml encoding failed.character encoding conversion failed.)

what does this mean?

Please help me.

And why sometimes i run the asp program,it work.but sometimes i run the same it can't work?

another question is i think is also server problem.
for eg.
the program list 4 selection to choose.After u choose, the information displayed on the screen.
when i choose first selection,the information successfully displayed.but when i choose another like third selection, it failed to work.(the error occur-can't load filename.asp)
Why?


please help me to solve and explain the cause and solution to me.
Thanks alot.