Random thumbnails do not show

[jarendt]

I have 1.4.10.
IIS 7
PHP 5.1.6
MYSQL 5

http://photos.itshop.ca

Random thumbnails do not show up.  If I hit refresh, thumbnails that did show up now don't and thumbnails that didn't show up last time do.  So, all the thumbnails are there, just some do not show up at random intervals.  Any ideas? This didn't happen until I upgraded to 1.4.x from 1.2.x.
I've tried in both firefox and IE with the same results.

[Joachim Müller]

I refreshed the index page several times and browsed some categories - the random thumbs appeared fine for me every time. I guess this is something on your client. Check paranoid pseudo-security apps like "Norton Internet Security". Not related to installing, moving thread accordingly.