I used Gemini to help with this but I am not a programmer so someone else should take a look at see if it is correct (the plugin now loads though)...and I have not logged in yet to test.
The Fix
The .Select(x => x.userid) part is now redundant and incorrect because the elements (x) are already the player IDs (ulong). You just need to iterate directly over the authorizedPlayers collection.
The Solution is to remove the LINQ projection (.Select(x => x.userid).ToArray()):
Line 262, Code should like the following:
private bool CupboardAuthCheck(BuildingPrivlidge priv, ulong hitEntityOwnerID)
{
// string hitId = null; // These lines are no longer needed
// string entowner = null;
// Iterate directly over the authorizedPlayers collection, which now contains ulong IDs
foreach (var auth in priv.authorizedPlayers)
{
if (auth == hitEntityOwnerID)
{
return true;
}
}
return false;
}