The first thought that comes to mind is that although the user has access to the files and SQL database, it may only have read access. The user requires full access to the data and files within the Kartris folder.
Please review the documentation on installing Kartris manually and pay attention to the setting of permission for both folder/files and for the database.Section 2.4.2 of the following page...
http://userguide.kartris.com/Default.aspx?headID=26Should you copy the files from the installation .zip over again, make a copy of the web.config file in the root directory and retain this file as it contains all your personalised settings. If the problem persists you may want to try forcing the setup routine in section 2.4.4. of the same document.
Do you know which version of IIS you are running?
Is the install on a server accessible publicly?
I can confirm that both IE9 and IE10 have no issues when accessing Kartris. A different browser should perform no different.