If you look through the agreement you signed with your broker when you opened your account, I bet your broker reserved the right to restrict trading when they deemed it necessary.
I've seen several other brokers do that on occasion.
For folks who can't buy a stock on-line through your broker, I believe you can call them and have your broker execute the trade for you; and they will charge you the standard on-line commission fee, the one you pay when you buy stocks on-line, not the 25 or 30-dollar broker-assisted commission fee. Check with your broker... not that there are many people who want to buy HCPC stock right now though.
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