Minions and any other non-champion friendly or enemy (not Monsters) indicators shows as blue and black squares respectively. This includes wards and Caitlyn traps.

This was on live servers but I thought it would be best if I post it here.

Hey Poleshoe, for bugs you have on the live server you should post here:
http://na.leagueoflegends.com/board/...isplay.php?f=3

Specifically to your error, it sounds like you need to repair your client. To do that, open the patcher and click on the gears on the top right corner. A window will come up and you can click on Repair.

I actually saw this happen last night! Glad it wasn't just me.

As Lemon stated previously, this is most likely a missing or corrupt file error with your PBE/Live Client, repairing it should fix any and/or all missing texture files. It happens occasionally and is easily fixed, although somewhat time consuming. If repairing your client does not fix the issue, file a support ticket through support tab in the upper-right next to the account button. After getting onto the support page, click on the 3rd tab to the right, where it says "Submit a request." If nothing else helps, Sit on your hands and swing your legs wildly while pouting, this should make you laugh.

~Summoner namora, of the lower case.

I reported this as well, but it just got swept away with the many other post.