In the BoincTasks log I see Unable to read gui_rpc_auth.cfg, is there such file?

[fred]

A tool to fix this problem: http://www.efmer.com/download/boinc/AddToGroup.zip

It will grant you access to the boinc folder where the password file is located.

Unzip the program.

Run the program as administrator (right mouse).
In the left bottom type in your user name and press "add user"

Restart BoincTasks.

[coolstream]

Nice addition. I have always created the file manually.

It would make a useful addition to add this to the BT  installer with a check to see if the file exists or not, don't you agree?