I believe it must be due to a wrong combination of packages. I have the same problem now with a document I'm writing (MiKTeX 2.9 on Windows 7), but when I open an old file I have that uses a .pstex figure, it compiles normally. The old file is \documentclass{article}, but for the new one I'm using llncs from Springer. Don't know if that's the difference, though.
I believe it must be due to a wrong combination of packages. I have the same problem now with a document I'm writing (MiKTeX 2.9 on Windows 7), but when I open an old file I have that uses a .pstex figure, it compiles normally. The old file is \documentclass{ article} , but for the new one I'm using llncs from Springer. Don't know if that's the difference, though.