POM- Often, the site is down for only a few minutes at a time. I think that it is a coincidence that apparently you seem to get the message when you are on Firefox. There is no connection.
It can not be a coincidence when it happens continually and consistently and has happened in this same way for more than a year. During the first few months that the public library (principle place of internet use) subscribed to Firefox, I could not access A2k through it at all.
The librarians use the phrase, "not all sites are compatible with all servers," to answer customer problems with access.
The same sequence happens when I am at my friend Gail's house, using her computer. For the first week of school, when only the teachers were in, and there was open access to this forum (it is blocked otherwise), the phb: Critical Error Could not connect to database message appeared only when logged on through Firefox and not when logged on through IE. You can attempt to access a2k through firefox for half an hour sometimes and get the message, then switch to AE and log in. However, AE will be slower.
I recently used my former boyfriend's computer and experienced a different set of snags. I receive notice of postings -- both here at a2k and from another forum I use -- in my inbox. I signed on the answer a post on a2k but had to relog on again for each post. Because of that, I was unable to access the other forum at all.