Pass php var as form value

[flashpipe]

Not sure why this isn't working, but I'm setting a variable in a form:

<input type="text" name="total_total" id="total_total" size="15" />

and updating it from another field:

<input type="text" name="num_reception" id="num_reception" size="15" value="0" onchange="document.myform.total_reception.value=75*parseInt(this.value);document.myform.total_total.value=75*parseInt(this.value);" />

and that works fine. However, when I try to pass that value to the next page, I get errors...

This works fine...

<input type='hidden' name='pg_total_amount' value="50" />

This gives a "You are not authorized to view this page." error:

<input type='hidden' name='pg_total_amount' value="<?php echo $total_total ?>" />

This gives an error that the value must a number be greater than 0:

<input type='hidden' name='pg_total_amount' value='total_total' />

Any ideas how to do this??

Thanks!!!