Weird..never had that problem...I haven't had really any bugs...weird..
Incidentally, your screenshot is a perfect one to show the bad textures. You can see the distant rock walls look great, then that one up close on the front right...what the heck?
http://cloud.steampowered.com/ugc/595827796571545694/3A984D33ABB09AFCFF3C42BE1BF6FF66FBE633FE/
TBH, I didn't even notice -- was too busy dealing with weird mouse and framerate issues at the time I took that shot. I'm not surprised, now that I've gotten out into the rest of the world -- I've had issues with textures showing up just as pink blobs for whole suits of armor. I suspect their texture streaming code is running into either timeouts or failing to actually handle the load of some of the assets. Annoying, but not something too difficult to fix.
Personally, I'd much rather see them fix the shadows problem some folks are having where the framerates drop drastically to the point of being completely unplayable.
Who says they are flash files? Just because they're labelled SWF doesn't mean they are flash files, try opening them first with VLC.
They could stand for Skyrim Word Format.
I say they are, and so does the http://linux.die.net/man/1/file, which looks at the files innards to identify what exactly it is. See also this transcript:
compute:~$ file widgetoverlay.swfwidgetoverlay.swf: Macromedia Flash data (compressed), version 10compute:~$