Hi All,
I ran into the same issue earlier today and managed to get it working, so I wanted to share the solution in case it helps others.
In my case, the error was caused by an invalid path name. The SaveFileBytesToUserTempFolder function saves the file to the temp folder, and then my dashboard button tries to open that path. I was using a |UserName| substitution variable in the Navigation Arguments. However, since the username contained spaces, the system couldn't locate the path correctly.
To resolve this, I created an XFBR rule to trim the spaces from the username, and now everything works as expected.
