What exactly do you mean? Do you have a poly plane with a movie or file texture assigned to it and can't get it to go? If that's the case, open the attribute window for the file or movie texture. Under the "Reload File Texture" button is "Use Frame Extension." You have to check this, then click the B&W box to the right of it. In this window, you will have to create an expression to make the movie frames play. Type...

file1.frameExtension = time + 1;

then click "create." Note that your file texture may be "file1" "file2" etc. Make sure you insert the right number in the expression.