@geoffbland No problem. 🙂 It's the first time I see this error with tapdisk (and it's it's even more surprising to have it on this type of SR...).
It had all been working fine and I had not changed anything on the share - it just stopped working
In this case, maybe there was a problem with the XAPI, a lock on the device or something else. Not easy to find the cause without remote access. Don't hesitate to ping us if this problem comes back. 😉