All the files don't contain any viruses! If your antivirus detects some files harmful or dangerous, let you know that some files are modified by me and, of course, the antivirus could detect it as viruses! I guarantee that all the files are original, don't contain any harmful codes etc.
mIRC Korona always is installed as portable version, if even you run AlexScript.exe as installer, the installer just copy the files to the chosen directory. It doesn't create uninstall info or something else.
Preferable to run mIRC.exe with administrator rights, otherwise install the script in a folder where you have the full access of it!
Be sure you don't have restrictions on the system!