Invalid MEX file - Not running

Setting up Psychtoolbox on my new Linux (Ubuntu) OS.

Getting this error "Invalid MEX-file '.../Screen.mexa64

The file exists and is in the right directory.

I am unable to run it like every other MEX file, is there an easy fix such as the possibility to redownload that particular MEX file? I tried redownloading Psychtoolbox but it made no difference...

[Walter Roberson]

Is it possible that you are using a 32 bit Linux?

[Marek Galus]

Screen function was not working since I didn't have GStreamer downloaded.

Works now!