Man, this exchange is terrible. Not only does it look terrible, barely usable, but I too cannot withdraw my coins due to the invalid address issue (for a perfectly valid address).
Also most of my coin deposits were getting stuck, so I had to manually paste the transaction into the site for it to synchronise. This seemed to work.
anyway to get my 579~k of imperialcoin back? like your coin address, mine is definitely valid but whenever I input it, coins-e tells me that its invalid. Im just wondering if you ever got your issue resolved, and how? Whenever i try to withdraw i get an invalid address error. Ive tried emailing them, ive opened up a support ticket about two weeks ago, and nothing, and I just came upon this forum, and man, I wish i'd added the deposit to cryptopia instead...