Label Files Corruption

We have designed our own invoices in Axapta. However every day the system seems to lose the labels for the invoice print. As a result we have to go into the Axapta top menu, Tools /Development Tools / Label file wizard and call up the labels three digit code which has already been created, every day so that the labels can be refreshed. Once this has taken place the OInvoice format is correct. Is this a common problem in Axapta or am I missing something? Your help would be appreciated.