It's just a touch too tall - your sig is 451 x 250 pixels and the size allowed is 500 x 200 pixels. If you can cut it down a little bit, it should be fine.
Adding the signature rules for you too.
Signature Lengths
Users should be considerate of other users on the forums. Excessive signatures cause the flow of the threads to be disrupted. Signature lengths over 10 text lines will be removed from user's profiles. This also applies to graphics that are larger than 500 x 200 pixels in length and width size. It doesn't matter how big the font size is as long as the total dimensions taken up by the signature text & graphic does not exceed 500 x 200 in pixel length and width.
So the total dimensions of the signature should not exceed this size:
Also, the file size of the signature should not exceed 200KB. We impose this limit as a courtesy for those on dial-up.