Such apparent anomalies might be explainable if we had a reference to the relevant games and move numbers. Suffice it to say, castling works here and games which are declared won are declared so by a specific set of non-arbitrary rules. So, supply the community the games and move numbers and we'll see if we can be of some help in providing an explanation.
apparent malfunctions in game operation

you have to show the games. it's likely that you are missing something on the board: a piece preventing you from castling, a guarded piece, etc. we have hundreds of thousands of games played online each day, and we'd know if there were problems in the rules :)

darryl,
Go to your game archive (either My Online Chess or My Live Chess), find the game or games. Click View on the game of interest. Scrape the URL from the browser's URL field and post it here, like this:
http://www.chess.com/livechess/game.html?id=174298679
Also, tell us which move or moves you believed were anomalous in your view. Be as clear as possible in explaining what you think you did or saw.
I'm new here but I'm an experienced player.
Several of the games I've played here have operated erratically.
Examples:
[1] Castling is not consistent.Sometimes it's worked but other times it's been prevented by the software, no matter what approach I try ( moving the K directly across or moving K off the board to new square)the rook is locked to it's position.
What's the deal?
[2]Games ended by fiat & "winner" declared, even when a valid move is available to get out of check or to capture attacking piece.
Ex: B captures piece next to K, King could take B with no threat but move is not allowed.
Again, what's the deal ?