sudden lookup failure

[hex44415a]

I`m looking for help with a problem with a lookup. I created a memebership Database and to simplify things i added a postcode / address /town /county table which automatically searches postcodes input into the " members" table and fills in the rest of the relevant details for the member. All was working great adding the data to both tables as records were created. Started this morning to carry on with the database to find that the records are being added in "members" but not copying over to postcode table. Nothing has changed within the database except for a button movement to a different layout.( even reverting the button back to original layout hasn`t solved the issue)

If anyone knows why it has done Please help.its driving me crazy

[imoree]

Umm. post a file or a little more information if you would like someone to help ..