Martin,
I noticed you uploaded a 1.2 version to handle errors a bit more gracefully. Though I’m sure not the most interesting of "features" to enhance, I’ve managed to still get Media Center to come up with invalid application and some other anomalies. I guess I’m just a little anxious for Last.fm to fix their authentication so I’m still just playing around in the mean time.
Anyway, in case you are interested, here are the steps to reproduce:
1. Removed HKLM Songler registry keys.
2. Open Songler.
3. Click Preferences, enter credentials, click Save.
4. Observe “Error authorizing” message.
5. Click OK.
6. Click Back.
7. Close Songler.
8. Open Songler.
9. Click Preferences and credentials already populated.
10. Click Save.
11. Observe message “Last.FM Username and Password validated as non-premium subscriber…”
12. Click OK.
13. Click Back.
14. Close Songler.
15. Attempt to Launch Songler.
16. Observe “Invalid Application.”
17. The only way to get it to launch again is to remove registry keys.