Phone number no longer going in database

I have an issue where the phone number is not being written to the database.

Only difference between now and then is an upgrade to Php 5 by my hosting company as they moved my site on to a faster server.

Can any one help with the syntax need to cuer the issue.

Using version 1.3.7. I have been through the tpl_module_createaccount.php and the modules/create_account and nothing seems to have changed. BUt I am not a programmer so cannot understand why every other field is being posted okay other than this must be something to do with numbers verses text fields.

Desparately need help as I cannot contact customers as I don't have the phone number and this is a live site (works locally on older version of PHP)

Thanks