Module Variable 7.x-1.1 upgrade breaks website

I have inherited a website that was not well maintained for a longer period.
In the mean time I have upgraded the all modules and kernel to a recent version. I also had to migrate to a new webserver to have a more recent version of PHP.
The only element that I can not upgrade is variable.

I currently have variable 7.x-1.1
Drupal kernel is 7.32
Internationalization 7.x-1.11

as documented in https://www.drupal.org/node/1670274 I tried to upgrade first to 7.X-1.2, but that did not work, the update.php script still would not run (because of the check wants at least 2.0).
I tried all other versions of variable available (2.0 till 2.5). I always have the same result: the update.php script does not run (or gets stuck while running, I guess) and the website breaks: theme is gone and multiple error messages are displayed:
"Warning: file_get_contents(): Filename cannot be empty in _locale_parse_js_file()"
only option is to restore back to where I started.
I always cleared the cache in the database itself because in drupal I cannot clear the cache: it returns this error:
PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'paasfees_drup1.drup_cache_panels' doesn't exist: TRUNCATE {cache_panels} ; Array ( ) in cache_clear_all()

Does anyone have any idea how to get out of this situation?
tx