user event script error when mass update

Hello,

I created a user event script (before submit function) on inventory part to fill page title field with specific formula depends on other fields in the record.

after that, I do mass update for some records, but it returns error because of the script.

In my script I added if statement to check if store display name field not equal null, If yes: fill the page title with the item code + item store display name, but when I try to catch the error with the following syntax:

catch (e)
{
var x= e.getCode() + " " + nlapiGetFieldValue('itemid') + " " + nlapiGetFieldValue('displayname');
nlapiSendEmail(****,'MY_EMAIL', 'error occurs', x);