I found out that you can't send a variable quantity to Paypal mobile optimized pages so I changed to this and it now works.
<form action="https://www.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_xclick" />
<input type="hidden" name="bn" value="webassist.dreamweaver.4_5_0" />
<input type="hidden" name="business" value="ryanbalthrop@gmail.com" />
<input type="hidden" name="item_name" value="Fall Together CD" />
<input type="hidden" name="item_number" value="mobile_falltogether" />
<input type="hidden" name="amount" value="15.00" />
<input type="hidden" name="currency_code" value="USD" />
<input type="hidden" name="shipping" value="1.95" />
<input type="hidden" name="return" value="http://ryanbalthrop.com/transactionsuccess.php" />
<input type="hidden" name="cancel_return" value="http://ryanbalthrop.com/transactionfailed.php" />
<input type="hidden" name="undefined_quantity" value="0" />
<input type="hidden" name="receiver_email" value="ryanbalthrop@gmail.com" />
<input type="hidden" name="mrb" value="R-3WH47588B4505740X" />
<input type="hidden" name="pal" value="ANNSXSLJLYR2A" />
<input type="hidden" name="no_shipping" value="0" />
<input type="hidden" name="no_note" value="0" />
<input name="submit" type="submit" value="Buy Fall Together CD">
</form>
