Hi Crompton,
That error and the crashing issue definitely sounds inconvenient. This usually happens when AccountRight tries to open a document in the In Tray, but the PDF reader on your computer is either missing or corrupt.
To fix it, you can try setting a different PDF reader (like Microsoft Edge, Adobe Reader, or Chrome) as the default, or reinstall your current one if you'd prefer to keep using it. If you need a hand with this, we'd recommend getting in touch with an IT professional.
Here's a handy link on how to change your default programs in Windows: Change Default Apps in Windows - Microsoft Support.
Regards,
Sai