Hello,
some days ago my CC2.2 (RH9based) did not start because data integrity check of an mount point / partition (ext3), 30 pages with several errors(Inodes)were scroling.
SO I deleted this mount point in the fstab and restarted CC.
I checked the partition with fsck -n -> no errors found.
By using fsck -nf 6 errors were listed.
After repairing with fsck -pf, fsck -nf reported everything clean.

1.Is my partition now clean?

2. What error checking/correction is used after an uncomplete shutdown?

3.What error correction modules / programm are available and perhaps better than FSCK ?

fsck is the only thing you can use. the filesystem is most likely clean, but whatever files you may have been working on when the machine was reset may be incomplete, or have bad data in them.
when the filesystem is loaded, a clean bit or byte is checked, and if clean, changed to unclean, i think. when you shutdown normally this is changed back to clean. that way if you boot, and the filesystem says unclean, then it knows to check.

This is still unanswered:
2. What error checking/correction is used after an uncomplete shutdown?