This is a question I get a lot from clients with highly modified SMF sites. The answer is simple:
If your forum was a plain installation then the update will probably find no errors.
Since your forum has many modifications the update code does not recognize the modified code and shoots an error message because it does not know how to proceed.
For instance, to have Adsense on your site you would have to modify x code on y page so it changes y page. When the update looks for x code on y page then it does not fix x anymore but a modified x.
Ignoring errors and installing anyway could bring your forum down as well.
, if you know something about "Why Are There Errors When Upgrading Or Installing On Smf?" under Computer Issues & Video Gaming then you can be the first to Reply to Why Are There Errors When Upgrading Or Installing On Smf?! You will then have 1 Posts and 1 Core Posts! now or scroll down for [Fast Reply] box.
I was hoping for more on why are there errors when upgrading or installing on smf? needs to be emphasized without delay how what are the ins and outs of it.