Changing Screen Resolution With VB 2005?

I'm having a difficult time converting a Windows API call that works fine in VB6 to run in VB 2005 (Windows XP with SP2 in both cases). I reduced the problem code down to its core which is below. I'm trying to change the screen resolution with the ChangeDisplaySettingsEx call; the idea is that on entering the program it shifts to high resolution and at the end it restores the original settings. I left the restore part out because I get the same error. Which is "An invalid parameter was passed in.This can include an invalid flag or combination of flags." I'm trying to use exactly the same parameters, but somewhere in the conversion process from VB6 a fatal change crept in. My guess is that it's either in the ByRef/ByVal or Short/Integer/Long alternatives, or in the conversion of the Devmode structure which included fixed-length strings (OK in VB6 but not allowed in VB.NET). But all my fiddling so far has not produced a solution. I got the same error code back in VB6 when I tried to set a display frequency that was not supported at the resolution I requested, but even leaving the values unmodified (in effect setting them to what they are now, with no change) gives the same error. Any ideas? So far as I can tell, there is no alternative to the API to accomplish this goal; would be interested to know if I missed it.

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