After installing Oblivion from scratch ( deleted the complete installation, inclusive all self made omods, etc.)
the same error occured while using the weOCPS.dll (from weOCPS_2009_03_28_upd-22282.zip at TesNexus),
and didnt after removing the dll.

This time I made sure no possible other error source due to incorrect validation, old meshes or textures, wrong ini's, old mod versions, wrong omod package, etc.
could be the reason, not the weOCPS.dll itself.

Could someone verify this? (if it happens that you have the same gfx glitch and use the weOCPS.dll,
just remove it from the Oblivion\data\OBSE\plugin folder and give us a short note if this did prevent the gfx glitch? tops: )

When you remove weOCPS.dll do you experience crashes where you used to get the gfx glitch?

No, definitely not.
Strange thing is, I have examined the weOCPS.dll logfile for some time now, and between all of app. 100 ctds (last two weeks), there wasnt one new entry in the weocps log. there are some then and now, but not between every ctd, which i usually experience after lots of running aound in exterior worldspace, usually when a cell switch is done, or when i enter a different location(different worldspace (IC) or interior (dungeon))

so, I made sure that weocps.dll isnt preventing much (..any) ctds before removing it.
Indeed, somewhere else i read, that weocps.dll does cause some additional ctds,
but there is no way for me to confirm that, subjectively the ctds are the same,
in amount and occurance, with or without weocps.dll.