We have seen some of xlsgate features have stopped working today. After researching 2 hours we could not find any bug, after a research in google we have discovered this interesting blog entry
If you get error messages in XLSApp which was not there before, such as “cannot create object” might be an indication for this bug
How to solve it
There are several details to be able to resolve this issue, please refer to linked blog entry for details and comments but generally you will need to open %temp% folder and locate all *.exd files and remove them. On our computer i could not delete them because they were locked by Excel itself. There was not a visible Excel App running on our computer, so we found like 20 Excel Apps running on our Task Manager, we have manually killed all of them in order to delete *.exd file, otherwise windows will not let you delete it. If you dont know how to work with Task Manager, reboot you computer, open %temp% folder and then try to delete it.
After deleting the *.exd file only part of my problems were solved, so i did a reboot and voila all my problems were solved. We strongly recommend you to make a final reboot