Sorry; I don't see the image.
However, it sounds like there's a conflict between Sophos' on-access feature and the process driving Intego Backup Assistant. If you (temporarily) disable on-access scanning prior to running the software, do you still get the error?
There have been other issues with certain backup systems not playing nicely alongside Sophos; Time Machine issues have mostly been worked around in the product, and most other major backup solutions have also been worked around, but I haven't heard of Intego Backup Assistant issues before, so there may be untested issues with that product.
Backup issues generally revolve around the timing of locking files for scanning -- if you have Live Protection enabled, you may want to keep on-access enabled and just disable Live Protection to see whether the decreased time files spend in a locked state fixes the issue.