On exporting PDF of donations and income from Tools > Export gives TCPDF errors.

There should not be any error.
Doesn't generate PDF and displays Error.
There might be possibility that solving this issue will solve the one in PDF Receipts add-on.
https://github.com/WordImpress/Give-PDF-Receipts/issues/129
@DevinWalker @ravinderk On further investigation, this issue is generated due to HTTPS of Local by FlyWheel as per http://local.getflywheel.com/community/t/make-https-work-from-locals-localhost/327/3. However, I've fixed the issue by changing the relative path with absolute path which works for HTTP as well as HTTPS.
Most helpful comment
@DevinWalker @ravinderk On further investigation, this issue is generated due to HTTPS of Local by FlyWheel as per http://local.getflywheel.com/community/t/make-https-work-from-locals-localhost/327/3. However, I've fixed the issue by changing the relative path with absolute path which works for HTTP as well as HTTPS.