Toshiba has issued statements saying that e740 Pocket PCs in the affected range may experience a loss of data if the battery is allowed to fully discharge. Data may also be lost if the battery is disconnected from the device for any reason.
If your device is in the affected range you are asked to please contact Toshiba at 800-788-1653. A customer care representative will make the proper arrangements for the exchange.
If your device is affected and you would prefer not to return the device Toshiba recommends that you make regular backups of your data. They also say that you shouldn't fully drain the battery that you should connect the device to an external power supply before disconnecting the battery.