Problem in smoothing tile moving logic

[yeloshu]

To help to emulate the movement from Pokemon as accurately as I can, I recorded a video of the trainer walking in a circle in Pokemon Red and watched frame-by-frame to see what the trainer did each frame. Here is the pattern I noticed:

Frame 01: Move 2 pixels
Frame 02: Change to Standing Frame
Frame 03: Move 2 pixels
Frame 04: Move 2 pixels
Frame 05: Move 2 pixels
Frame 06: Change to Walking Frame 1
Frame 07: Move 2 pixels
Frame 08: Move 2 pixels
Frame 09: Move 2 pixels
Frame 10: Move 2 pixels

On Frame 11 he'll change to the Standing Frame and stop.

If you keep holding the button, the sequence becomes:

Frame 01: Change to Standing Frame
Frame 02: Move 2 pixels
Frame 03: Move 2 pixels
Frame 04: Move 2 pixels
Frame 05: Move 2 pixels
Frame 06: Change to Walking Frame 2
Frame 07: Move 2 pixels
Frame 08: Move 2 pixels
Frame 09: Move 2 pixels
Frame 10: Move 2 pixels

and then alternates between that and:

Frame 01: Change to Standing Frame
Frame 02: Move 2 pixels
Frame 03: Move 2 pixels
Frame 04: Move 2 pixels
Frame 05: Move 2 pixels
Frame 06: Change to Walking Frame 1
Frame 07: Move 2 pixels
Frame 08: Move 2 pixels
Frame 09: Move 2 pixels
Frame 10: Move 2 pixels

I wrote my code so that it would set you into a moving state when you tap a direction, it increments the frame by one, then it does one of the above actions based on what frame it is. Somewhere though, there must be a problem. Sometimes, when you are moving around, the trainer's position will somehow be offsetted a little bit and he will be halfway in between tiles. I'm not sure what the problem is, or even where it is, but it's a big problem and I need to get this fixed pretty bad as it is kinda vital to working on the rest of the game. Also, I can't really consistently reproduce it with the same set of movements, but if you just move around randomly, it'll probably happen more than once. Any help would be much appreciated, thanks.

Project: http://cid-168f84f535deaf6d.skydrive...20Test%201.rar
Pasteall Link: http://pasteall.org/1202/csharp