i have this problem too, for the past few days i can't report any spam. A few days ago loading the spam report started to work very slow but eventually it got there... now i can't load it at all. From how it looks on my end, this looks to me like a network router/switch/network interface that's cooked rather than a hdd problem...
NOT always... in my experience when i tried reporting some spams that had ALL headers filled with my email address [at]gmail spamcop only removed it from the to: /cc: fields but left it unfiltered in the from: (it was a faked sender) and some other fields commonly added by hosting providers and used for their internal routing. it also left my user name unfiltered in the body of the email (it wasn't a full email[at]domain, just the user name). I had to cancel those reports.