When you convert the system hard disk to a dynamic disk, Windows Server 2003 logs:

Source: VDS Dynamic Provider 1.0
Type: Error
ID: 4
Description: The provider failed to load the disk into the cache.
Disk: \Device\Harddisk1

This behavior will occur if after starting the conversion of Disk 0, you use Disk Management to convert another hard disk to a dynamic disk, while Disk 0 is still being converted.

When you restart your computer, both volumes are mounted, resolving this problem.

Since both volumes were successfully converted to dynamic hard disks, you can ignore this event (assuming you restart your server).

NOTE: The System Partition is the partition that contains the startup files, NTDetect.com, NTLDR, Boot.ini, and possibly Ntbootdd.sys. The Boot Partition contains the system files (%SystemRoot%\System32).