This particular error only comes up on Windows servers that have had StorageCraft products installed. Because StorageCraft installs their own Volume Shadow Copy driver it renders every other piece of backup software on that system inoperable when it comes to shadow copies. StorageCraft's recommendation is that you should not use more than one backup tool on a server.
Quick way to get around this is to remove either AhSay or StorageCraft. If you prefer to keep both, make sure you turn off AhSay's VSS capabilities, so it does not fail.
Note: AhSay is working on a workaround to this issue but will work with a server where StorageCraft has replaced the VSS driver if VSS functionality within the agent is turned off.
OBM 220.127.116.11 fixes the problem. Tests ran without error.
The problems are resolved in the latest patches, which can be downloaded from http://download.ahsay.com/support/post-release-patch/obm.zip (for OBM), and http://download.ahsay.com/support/post-release-patch/acb.zip (for ACB) For upgrade instructions, please visit http://forum.ahsay.com/viewforum.php?f=1