Upgrading to 2.91 breaks windows installation

[Charlie Heard]

I run my account on Windows as a user, with a separate (unused) account with
admin privileges. I've been ill for a few days and noticed that a couple of
radio programmes wouldn't download in the PVR. I realise now it's most
likely another issue, but I assumed it was because I hadn't got around to
upgrading to 2.91. So I downloaded the upgrade and installed it.

The install needed to run with administrator privileges, so I entered the
password for the admin account (called "HP6300"). Now get_iplayer fails with
an error (which is wrong, in that the file doesn't exist, but it doesn't
have privileges to create a directory in another user's directory):
ERROR: Could not create dir 'C:\Users\HP6300\Desktop\iPlayer Recordings':
mkdir C:\Users\HP6300\Desktop\iPlayer Recordings: File exists; Cannot create
a file when that file already exists at get_iplayer.pl line 4304.

I'm not sure why this should happen now, as I've run with this setup for a
while with no bother, including previous upgrades. But I'm struggling to
find the settings that point to the wrong account/directory and change it to
the correct directory. I can happily download manually using "--output", but
entering the correct output directory in the PVR doesn't work...

Any help gratefully received
Charlie