Hello,
I have the same problem
I am using a fresh installation:
Parallels Plesk Panel v11.0.9_build110120608.16 os_Ubuntu 10.04
Ubuntu 10.04.4 LTS
and got also the error message:
2013-01-28T23:42:55+01:00 ERR (3): Apache config (13594129740.95481800) generation failed: Syntax error...