Does it give any other information with the disconnect (line 1)? The rest just shows normal connect information, so doesn't help to solve the disconnect problem. Are there messages above that disconnected line that may show more detail about the disconnection? Normally, if it just says Disconnected, it is because you (or your script) chose to disconnect. If it was some other cause, it would usually include more detail, such as the common 10053 software caused connection abort error message.
If all that is shown is * Disconnected, then you might want to try disabling all of your scripts and see if you are still disconnected. You could have a script that is disconnecting you.
This is the information I just get:
[14:45:45] * Disconnected
[14:45:48] -vesta.nl.eu.SwiftIRC.net- *** Looking up your hostname...
[14:45:48] -vesta.nl.eu.SwiftIRC.net- *** Checking ident...
[14:45:49] -vesta.nl.eu.SwiftIRC.net- *** Found your hostname
[14:45:52] -vesta.nl.eu.SwiftIRC.net- *** No ident response; username prefixed with ~
[14:45:52] * Attempting to rejoin channel #armia_polska
[14:45:52] -Global- [Wiadomo¶æ powitalna - Sie 05 2010] We will now perform a passive scan on your IP to check for insecure proxies. These scans are harmless and will originate from 220.127.116.11 and 18.104.22.168. If you do not consent to these scans please disconnect immediately.
[14:45:52] -Global- [Wiadomo¶æ powitalna - Pa¼ 24 2010] There have been several attempts recently by someone pretending to be a SwiftIRC service for the purposes of obtaining users' passwords. This is a friendly notice reminding all users that you should only enter your NickServ password through NickServ. E.g. /ns id yourpassword. Please exercise general password safety and know that the SwiftIRC staff will never ask you to state or confirm your password - Thanks.
There's nothing above the disconnected line. I do not chose to disconnect and I don't have any script (only some things in "Aliases", like /id or shortcuts to channels) and normal things in popups). It happens even if I'm afk.