Custom Output Errors

[porl]

I am running Hero Lab via Wine in Linux, so the following may be due to that. However everything else, including saving to PDF or exporting stat blocks, works flawlessly so I'm hoping it is something else.

Whenever I choose "Save Custom Output", no matter which option I choose I get the following:

An error was reported: NULL error description

If I choose any of the options other than the "Generate XML File" one I get further errors about missing lwdcustom.xml, although I believe that is because of the previous error.

I am running a completely new install of Hero Lab (just purchased today) and this happens no matter if I create a new portfolio or import one that has been made by someone else.