need help editing data with a userform.

Hello.
I am a Business Development Coordinator for the Scottish Prison Service and have currently been tasked to create Dashboards for different areas. Whilst implementing some of these Dashboards I realised that some of the users aren't too familiar with packages, so in order for my Dashboards to be user-friendly for data entry i have started to use User Forms. However, in one of my forms i can't get part of it to work properly.

In my form i have text boxes, combo boxes, option buttons and a list box. when i enter data into the text boxes etc. and press add, it adds the data to a table. the list box is used for a search button so that when i type into a text box some data and press search it uses criteria and populates the list box appropriately. when i double click the data in the list box it populates the text boxes etc in the user form so that i can edit things that need to be edited. However, when i press the Edit button it gives me "An Error has occurred The error number is:91 Object variable or With block Variable not set".

The only thing that is bugging me is that i have used the exact same code for another form using the exact same format and the exact same names for the text boxes etc. but i just can't seem to get it to work.

i have attached an example file to look at for anyone to help me please ?