# screen problems

**URL:** <https://psychtoolbox.discourse.group/t/screen-problems/1313>\
**Category:** Uncategorized\
**Created:** [September 16, 2002, 1:57pm UTC](https://psychtoolbox.discourse.group/t/screen-problems/1313 "2002-09-16T13:57:05Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)\
**Post date:** [September 16, 2002, 1:57pm UTC](https://psychtoolbox.discourse.group/t/screen-problems/1313/1 "2002-09-16T13:57:05Z")

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hi - I see this has come up before, but I can't find a satisfactory  
answer:  
  
running the demos (as well as other script) in the latest  
(post-august 5) version of Psychtoolbox (matlab R12, windows 2000,  
pentium 4), I constantly get the following error...  
  
DLL load failed for mex file  
C:\matlabR12\toolbox\psychtoolbox\psychbasic\Screen.dll  
The specified module could not be found.  
  
??? Invalid MEX-file  
  
Error in ==\> C:\matlabR12\toolbox\psychtoolbox\psychdemos\GratingDemo.m  
On line 15 ==\> window=SCREEN(whichScreen,'OpenWindow');  
  
  
does anyone know what the problem might be?  
thanks very much  
chris summerfield