Personal value list dump error

While doing F4 help search for the Activity type field generally it should pop up with personal value list bt now it s giving dump error.

I have done setting in Help>> Setting>>F4 Help>> Do not display personal value list automatically>> Set the Indicator.

Now its showing complete list of selection while F4 Help in Activity type field.

This action can't be done because of it disable all other personal value list of user.

Pls help me to delete personal list for Activity Type because I am not able to access personal list any how for F4 help search from this particular field.

waiting for your response..

Thanks

Rakesh