Hello! I'm running Win7 and using Chrome. On the page "http://subeta.net/wardrobe.php" I was incorrectly rewarded the "Filled Wardrobe" achievement. I am still new to the game and and as of right now I believe I only have 6 items in my wardrobe.

It looks like the first tier of the Filled Wardrobe achievement is 5 items :) So you should be alright. There are 25+ tiers of that achievement, so you achieved the first one.