Error when deleting users

Hi,

I have the a similar problem like here #361380: Error when deleting users, but with the 6.x-1x-dev version.
When deleting users, I see the following error:

    * user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM activity WHERE uid = 4)' at line 1 query: DELETE FROM activity_targets WHERE aid IN (SELECT FROM activity WHERE uid = 4) in C:\xampp\htdocs\mysite.com\sites\all\modules\activity\activity.module on line 444.
    * user warning: Table 'icfn_03.actvity' doesn't exist query: DELETE FROM actvity WHERE uid = 4 in C:\xampp\htdocs\mysite.com\sites\all\modules\activity\activity.module on line 445.
    * user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ')' at line 1 query: DELETE FROM activity_targets WHERE target_uid = 4) in C:\xampp\htdocs\mysite.com\sites\all\modules\activity\activity.module on line 449.
    * user warning: Table 'icfn_03.actvity_history' doesn't exist query: DELETE FROM actvity_history WHERE uid = 4 in C:\xampp\htdocs\mysite.com\sites\all\modules\activity\contrib\activityhistory\activityhistory.module on line 41.

Can anyone help me, please?

Regards,
Stefan