After installing and enabling ffc 90% of all modules were disabled automatically!

I installed field formatter class module and Field Formatter Settings API module in one go. After this, i got notices:

Undefined offset: 1 in _drupal_parse_response_status() (line 1112 of /html/includes/common.inc)

Undefined offset: 1 in drupal_http_request() (line 984 of /html/includes/common.inc).

and almost every module that was installed and enabled already got disabled automatically! The site wasn't working anymore but i could retrieve it by enabling all the modules again. Did anyone of you experienced something like this? Does this imply that a serious problem is buried somewhere?