MACRO - Not Enough System Resources to display correctly

I have a marco that I am using to do simple data input into a master spreadsheet - of which I aggregate later - When I invoke the Macro with CTRL-B I get a weird "Not Enough System Resources to display correctly".

I have no idea where to start with this error. It's rather annoying and I can't see to find a way to rid myself of it.

Screen capture attached.

Suggestions are welcome! Thanks.