Invalid at the Top Level

[alcanallen]

Hi could any one explain this error? i get quite a few.
Invalid at the top level of the document
Error on line 1,position in''''
Thanks,
alcanallen

 

[popsaka]

Sounds like a error in an '.xdp' file... yes?

 

[alcanallen]

Error!

I downloaded a mission with two files the one works the other has the error,haven`t a clue thats why i`m asking!