While I so very, very much appreciate the efforts of Atrophy and others to help those experiencing problems, I too have tried over-installing, uninstalling, reinstalling, calling my ISP to verifiy my capability of connecting, downloading the manual patch file and installing, and a host of other things that I won't bore everyone with -- I'm on the verge of agreeing with MrClastro, sadly.
I'd much rather enjoy the game, so if there is something else that has been known to work, please share. I had very few troubles until this morning, 09/25/08. I get to the screen where I put in my User ID and Password, and then "You can't access the server. Try again in a moment."
I am not running Windows Vista. I'm using Windows XP.
Update: 09/26/08
I uninstalled and reinstalled a total of three times now. I did a PC set back to a week in ago just to see if that helped - it didn't. When I click to start Trickster, it launches and does the check that gives the 'Client is latest version' message. I click start and it goes to the screen with the dragon and loads -- when I click game start, the User ID and password fields appear and I enter those, click log in and immediately get "You can't access the server. Try again in a moment." Help please. 
Update: 09/26/08
A little ray of hope -- I got through once! I hope it works again. :)