That sounds more like a boob than a bug.
Bug in tactics trainer?
Sort:
diagnosis: Oops.
remedy:
3 pints of Guinness (you may sub with Fosters "oil can"), 4 shots of Yager
sleep until you wake up naturally (do not use your alarm)
try tactics trainer again
send us a new post with the results
12 hours and counting
Dec 13, 2008
0
#5
What browser are you using? I have some problems also and gotten skipped rating.
As mentioned in my "edit" above, the third problem appeared in my history as "skipped". This occurred within two hours of making my initial forum post.
Since the third problem has now appeared in my history, I'm not surprised that I can't access tactics trainer.
I'm using firefox 3.0.4
I'll tell you what happened since it happened to me as well - this problem can occur when it still says "you have completed 1 of 3 allowed problems" when you click on the trainer button. That's what did it for me.
I've waited over 24 hours and it says I've done my three and can't do more. 
RedStateGreen wrote:
I've waited over 24 hours and it says I've done my three and can't do more.
Are you sure you followed the remedy exactly?
I also just got this skipped glitch. It happened (I guess) when on Firefox I pushed repeatedly start tactic trainer as the tactic trainer did not open itself. I got in by going to address: chess.com/tactics/server.html.
Here is the photo about it. My points are jumping up and down funnily ( I don’t mind really).
Hi all,
Sorry, I'm not sure where exactly to post/report this.
Site moderators should be able to view my past tactics history and in particular, the time of my last attempts. You should be able to see that I've only done 2 tactics in the last 24 hours but the site states that I've completed 3.
I believe this occurred because I pressed the "Start training" button on this page:
http://www.chess.com/tactics/myhome.html
while the popup window from tactics was already open i.e. during training.
edit: the third problem has now shown up in my history as "skipped"