That is a normal error message one get when to try to use some support function that has dependencies. If what the function depend on does not exists the function is not currently available, You see this all the time in Photoshop UI. When menu items are grayed out the feature is currently not available because something the is required for the use of the function does not currently exist. Photoshop can not gray out a script statement. Photoshop put out that error message. Its usually a logic error in the script. However if the script usually work it may be it the document you using the script on is missing something. Sometime Adobe Also releases bugs that can cause that error. I could not use CS6 for five months till Adobe fixed the major bug they release in CS6 the first CS6 update fixed 506 bugs. Scripts that switch document would often fail with that message when CS6 was first released.