Suddenly in my server with Fedora 1 installed, the folder var is almost full, then when I restart the server some services like samba does not start due there is not space in folder var. I want to know what kind of files could I erase or if there is a kind of files logs that I can erase. Thanks

First thing to look at would be /var/log. This contains various logs as implied by its name. If you don't have logrotate running the logs (e.g. messages) could get extremely large. Files there can pretty much be zeroed out (e.g. > /var/log/messages) but some of them are activley in use (such as messages) so you should do:
before zeroing them out then afterwards.

Also try doing:
This will find core dumps (dumps of memory left behind by programs that died unexpectedly). These can be removed.

Also /var/spool subdirectories may contain things that can be removed as well as /var/mail.

Finnally doing:
Will show you any tar archives you have. Typically you can compress these by doing:
to free up space.

Yum in old versions of Fedora caches downloaded packages in /var/cache/yum which you can remove with "yum clean packages". The obsolete up2date also used to cache packages somewhere in /var I don't remember.

hey maybe you're config mounts /var as tmpfs. that surely will get full immediately. do 'mount' to check.