If you are familiar with the search feature in mirc then open the mirc editor (alt +r) and click on the "Find Text" button in the top right hand corner and in the Find Text edi box type close -m and click the "Find Text" button on the dialog and remove the line ther. When/if you find the text close -m make sure you read the code around it because you could remove something that isn't the issue. The line(s) should look like:

on ^*:OPEN:?:*:{
timer 1 1 20 close -m blah }

or something like that. There are other methods but when I am searchingfor ertian triggers within a script this is how I do it. Knowing mirc coding does help but you don't need to be a genius.