Recently encountered this one with Acronis Backup and Recovery 11.7. Backups were failing and throwing warnings saying
Failed to load addon: ArsAgentProvider.dll
Message: Cannot load the dynamic library
Event code: 0x00C10001+0x00000001+0x0000FFF0+0x8007007E
After a good bit of troubleshooting and searching, I found this article that says it applies to 11.5, but works for 11.7. Download the DLL file and throw it into your Acronis directory. The file was COMPLETELY gone from my directory, even after running a repair install.
The next backup I kicked off went through 100% successfully.