ok, I think the problem was solved.
Just in an incredible way...
After the Fatal error appeared, I do these things, trying the lower BST versions:
replace the files with v1.6 failed;
replace the files with v1.5 failed;
Reinstall the osc v2.2 RC 2a, and try v1.6, failed; v1.5, failed...
Reinstall the osc v2.2 RC 2a, and try v1.7, still failed due to without import the sql file. After I import that,
God revealed!!! Succeed!
I think that maybe have something to do with the Cache, for I simultaneously test two Osc shop on my computer, or other reasons I do not know.