Unfortunately, I can't access my admin area. And I don't have any backup.
I got a solution from online forum for smf users. But I couldn't get to fix it simply bcos I don't really know where to find template file.
The solution is this I managed to solve the problem manually.
I removed the simple ads template file. After doing this, the forum worked again, but it showed a new error (this time within the theme), about how the ads template file is missing. So what I did was reupload
the standard ads template file via file manager. This solved both issues. The site, including admin, was completely accessible again. I uninstalled the simple ads mod, and deleted it from package.
I hope ^^ that makes sense to anyone experiencing the same problem
I couldn't get in touch with the guy to explain a little more to me.
Timi Dapsin, how can I unravel this?