I installed wine on Ubuntu 8.10 from a repository which used to be listed on WineHQ. But now installed wine version is 1.1.42 while WineHQ has already released 1.2-rc5. Is Ubuntu 8.10 no longer supported? Or where can i find recent wine builds for it? I have tried using deb package for 10.04, but it has too recent dependencies. I wouldn't like to build wine manually on my EEE PC since it would take hours to complete...

Yes, it is no longer supported:
https://wiki.ubuntu.com/Releases
https://lists.ubuntu.com/archives/ub...ch/000130.html
I would strongly recommend doing a clean install, that is, not a dist-upgrade, of Ubuntu 10.04, which is the current version of Ubuntu.
Ubuntu 10.04 is a long term support (LTS) release. So the desktop version of 10.04 will be supported with updates for 3 years at least.
You should not continue to run an unmaintained version of Ubuntu if you are connected to the internet, since there will be no security updates for it.
FYI: The non-LTS releases of Ubuntu are supported for 18 months. You need to know when your version of Ubuntu will reach End Of Life if you do not compulsively upgrade to the newest version as soon as it comes out ... (like I do!!!).

I would like to do this, but there exist some blocker bugs in both 9.10 and 10.04 which make me still use 8.10.
Do i understand correctly that if Ubuntu version is unsupported by Canonical, its wine versions (released by WineHQ, not Canonical) also get unsupported?

What problem(s) are you having trying to install Ubuntu 10.04?
Anything that was in the Ubuntu 8.10 repositories will no longer get updates. In addition, when a version of Ubuntu reaches end of life, it's repositories disappear, so you won't be able to install new software from the Ubuntu repos.

If you can't get Ubuntu 10.04 to work, then I would try another distro.