Nightmare!! Good job you are one of the few people that have a usable backup/restore system.
But have you considered that your backup solution might actually be the cause of the problem?
Do you know at what point during the boot process your PC accesses the boot (MBR) record ? Is that when you get the message?
As I'm sure you know, RB modifies the MBR.
I notice that Acronis True Image Home 2009 contains the utility Acronis Startup Recovery Manager
"Boot your computer after a failure to start the recovery process simply by selecting the F11 key, even if your operating system has failed."
To do this it probably needs to modify the MBR, especially if the dual boot option is used.
I found the following comment at
http://www.wilderssecurity.com/showthread.php?t=233711
"The Acronis MBR contains a few hundred bytes of code that attempts a jump to the Acronis Secure Zone when the PC is booted. From there, if successful, it displays a message "Press F11 for Acronis Startup Recovery Manager...", which will give you the opportunity to boot into the Acronis Recovery Environment.
So if Acronis changes the MBR maybe it's incompatible with RB?
On the other hand there's evidence that the two can be run together ok
http://www.wilderssecurity.com/showthread.php?t=243277
but also in this thread can be found the comments
"According to Horizon if you image with other software with RX installed you will need to fix the MBR after you do a restore".
"FYI, as I understand it if you restore and image that was made with TI after you installed RX you need to fix the MBR when you restore the image and this can be done using a Windows install disk."
and
"It seems TI & Rx may conflict, after installing RX on this machine where TI 10 was already installed, I started getting frequent "Improper Shutdown" errors & chkdsk being invoked."
Also I know RB has problems if anything changes the disk that it can't log. Maybe booting from a CD or USB can cause this sort of thing if RB is not loaded first?
Finally, on a different tack, do you have an Iphone, touch phone or Ipod that you connect to your PC?
All of these seem to be linked to Google search results for "Magic data transfer".