Further info gathered after adding diagnostics:

Uninstalling directly after Installing attempts to update the %appdata% version of Scripts.ini
Uninstalling after ScrobblerDJ has been activated (ie play started) attempts to update the %appdata% version of Scripts.ini
Uninstalling as the very first action upon opening MediaMonkey attempts to update the Program Files version of Scripts.ini

Flushing the updated Script.ini file to disk seems to have solved the Installation inconconsistencies, but Installation always updates the Program Files version of Scripts.ini.

I have recently started experiencing problems with the Installation & Uninstallation of ScrobblerDJ V2.x that I believe is related to SDB.ScriptsPath.

It relies on a pair of vbs files called during Installation & Unistallation namely Install.vbs and Uninstall.vbs

Both use SDB.ScriptsPath to locate the Scripts.ini file and then update it to either add or remove a ScrobblerDJ entry consisting of:

[ScrobblerDJ]
Filename=ScrobblerDJ.vbs
Procname=ScrobblerDJ
Order=10
DisplayName=&ScrobblerDJ
Description=ScrobblerDJ
Language=VBScript
ScriptType=2

Here is the problem:

When installing as a non-admin user, the Install.vbs file updates the Scripts.ini in Program Files.
When uninstalling, the uninstall.vbs file (presumably) tries to update the Scripts.ini in %appdata%.

I say presumably because neither Scripts.ini gets updated during installation.

To compound the issue:

1) Frequently Install.vbs doesn't seem to update either version of Scripts.ini and I have yet to identify the sequence of operations leading up to this.
2) When the entry is added to the Scripts.ini in Program Files, the Last Modified date/time of the Scripts.ini in %appdata% is frequently also affected even though it doesn't appear to change.

(Note - All this occuring on a Windows XP system)