As many, I hate how AppForge "damages" my P800 - on the other hand I "need" a few AppForge applications. The following information is from support.appforge.com:
There is a known problem backing up Alarms.Dat on the Nokia Communicator. A problem with the same symptom also was present in the first release of AppForge Booster for the Sony Ericsson P800, version 3.5 Build 610.
On the Nokia Communicator, skipping the file should allow the backup to proceed.
On the P800, the problem with Alarms.dat is corrected in AppForge Booster for P800, version 3.5 Build 624 or later. You can download the current version of Booster at:
http://www.appforge.com/booster
You may continue to have problems with backup, even with Booster 3.5 Build 624 installed. The problem is with one or more files in the c:\system\recogs or d:\system\recogs directory on the device, with the extension ".mdl". These files are created to handle alarms that are set by applications. Installing AppForge Booster will create an mdl file on your device, RecAppForge.mdl. You may have other MDL files in this folder as well, depending on the other applications that you have installed on your device.
With the current version of AppForge Booster, backup will work correctly if RecAppForge.mdl is the only .mdl on the device. There is currently a problem with other .mdl files that may also prevent a successful backup. The workaround is to delete the additional .mdl files before backing up.
Similarly, you will not be able to restore if there are .mdl files on the device.
Depending on the version of PC Suite that you are using, you may not be able to see the c:\system\recogs or d:\system\recogs directory from the PC. If that is the case, you will need to install a file manager program onto your device to delete the .mdl files. Here is one application that we have found works:
http://my-symbian.com/uiq/applications/applications.php?faq=2&fldAuto=14
Note that the PC-Suite for the P800 seems to have other problems with backup and restore that are not related to MobileVB. In our experience, it is difficult to complete a backup or restore successfully, regardless of whether MobileVB is installed on the device or not. In particular, the communications link seems to be very sensitive to any sort of device timeout or interruption.
We continue to work with Sony Ericsson to provide better solutions to these issues. We will update this article when we have more information.