The file handling commands (/fopen, /fwrite, /fclose, etc) are probably not what you really need based on what you said. Those are best used for writing a lot of data. If all you're doing is adding a little information to a file, then you're better off with /write.
Whatever you do, you have to use an event to make them work. You cannot just put the commands by themselves into the remotes tab. For example, if you already get the information in your admin channel, then you can use the on text event.
Let's say that your data that is posted to your admin channel looks something like this:
Joined: Nick IP Date Time
An event for that might be:
on *:text:*:#adminchannel: {
if ($nick == botnick || $nick == altbotnick) {
write $3 $1-
}
}
That would write the line of data to a file named the same as the IP ("word" 3 in the example data, so $3). It will write only if the nick who posted the text is the bot's nick or the alternate bot's nick. That prevents writing data that isn't meant to be written. There are other ways as well that will let you prevent accidentally writing what someone is just talking about in the admin channel instead of only what the bot is telling you.
That's really just a basic example. If you want something specific, you need to provide an actual example of the data being posted to your admin channel and exactly what filename you want it written to and what you want written to the file.
To read the information, you'd use $read. Again, you need to put that into an event. You can use something like:
on *:text:!read *:#adminchannel: {
msg $chan $read($2,nt,1)
}
Then, anyone in the admin channel can type !read IP (IP being the actual IP or whatever you're using as the filename) and they'll get information from the file.
Of course, that only reads line 1. If you want it to read multiple lines, you have to loop it and you'll probably want to only read a small number of lines or else add flood protection to the script because otherwise you'll message out too many lines at once and get disconnected for flooding. You'll probably also want to message an error message if the filename doesn't exist.
Again, if you want a specific example, you need to provide specific information and details including what you want to input, what you expect the output to be, what you want the filename to be, and what you want in the file. And anything else that you want it to do.