my members cannot read some topics

hi, i have two problems,
1) in my forum i have 2 forum only for a few members and cannot enter, in my panel it is checked for enter, but they cannot enter! they must login multiple times in order to be able to enter
2) i want to delete a few members and i cannot do this, i know what i must do, but i can not check there! I have done this once and it worked, but now doesn`t work

my problem to delete a member its ok,now