[Konstantinos]

Your thread has lack of information about your first issue. You should've posted your server log. Did Whirlpool plugin fail to load? Do you have Whirlpool plugin loaded AFTER nativechecker? All those questions would have been answered by simply reading your server log (the part that loads the plugins).

About the second issue, KyleSmith already direct you to Wiki which explains it perfect. Beforing using fread/fwrite/fclose, you MUST check if the file handle (whether the file opened successful or not) is valid before using the variable that stores the file ID on those.
So if you do:

pawn Код:

new File: file = fopen(...);

you should have below it:

pawn Код:

new File: file = fopen(...);
if (file)
{
    // Use fread, fwrite, fclose inside here to prevent crashes.
}

Use debug info: https://github.com/Zeex/samp-plugin-...ith-debug-info
in order to get the lined caused the crash so you can fix it with the above way.