Hi Pål
What version were you using before ? This is not new in SP60, has been around from 15.7 ESD#2.
This is linked to certain security related restrictions that were put in ESD#2. Even if you are part of Administators group, you won't have automatic permissions on the errorlog.
As you state, you can grant specific users access to the file. You can do this for the 'sybase' or alternatively, grant all users of the host machine access (but that may beyond what you want). Use the steps above, and instead of the user id, enter (without quotes) "hostname\Users" followed by granting full control.
HTH
Bart