Input problem

I’m having a weird problem catching input from my users. Specifically on the Sprint Samsung A660. This works on every other phone I’ve tested. You can enter the mobile number, but when you get to enter the PIN it won’t let you enter anything. Eventually it will crash out the browser causing the phone to lock up and the battery to need to be removed. I’m at a loss. The input tag is the same for MIN (mobile number) and for PIN except for the length of the field. Any thoughts?


<card title='Sign Up' id='one'>
<p>

<fieldset>

MOBILE#:
<input name='min' type='text' format='NNNNNNNNNN' emptyok='false' maxlength='10' size='10'/><br/>

PIN:
<input name='pin' type='text' format='NNNN' emptyok='false' maxlength='4' size='4'/><br/>

First and last name:
<input name='name' type='text' format='******' emptyok='false' maxlength='25' size='25'/><br/>

</fieldset>

<a href='#two'>Next</a>
</p>
</card>

<card title='Sign Up' id='two'>
stuff card two does
</card>

</wml>