selecting item from selection control

Hi,

i have one issue in the va01 trasaction.

There is screen called Choose an unloading Point.

i am going to Seach and giving invalid and recording so.

My reqirement is if given value found it should continue.

if not it it suppress the error dialog and script should be exit by writing information to log.

Can any one suggest me the solution.

Thanks in Advance.

Regards,

sreedhar d