[Anonymous]

Here is what the form looks like before trying to upload a document:

And it's URL is:

http://devportal/Lists/Test/DispForm.aspx?ID=1&Source=http%3A%2F%2Fdevportal%2FLists%2FTest%2FAllItems%2Easpx&ContentTypeId=0x01005EB7D57568DE9246AD9D42DCC627741E

When I click Upload here is the URL:
http://devportal/_layouts/Upload.aspx?List=40c6c201%2Dfb8d%2D4336%2D89b1%2D82229064317e&Source=http://devportal:80/Lists/Test/DispForm.aspx?ID=1&Source=http%253A%252F%252Fdevportal%252FLists%252FTest%252FAllItems%252Easpx&ContentTypeId=0x01005EB7D57568DE9246AD9D42DCC627741E

And once I upload a document and/or cancel from this upload page that's when the above error appears.