Script is improved.
Super admin only.
Works with spaces.
Messages file path that was typed in confirmation message.
Just remember that you need to use / instead of \ for directories... Just type it in normally. What you did in your OP script was hurting you.
Anywho, here's the code:
//Utility_Exec.cs
function serverCmdexec(%client, %filepath1, %filepath2, %filepath3)
{
if(!%client.isSuperAdmin) return "";
%filepath = %filepath1 SPC %filepath2 SPC %filepath3;
%filepath = stripTrailingSpaces(%filepath);
exec(%filepath);
messageAll("" ,'\c5The file \"\c2' @ %filepath SPC '\c5\"has been executed.\n\c5Remember to destroy all bricks containing the item/vehicle you executed, and drop all of them! Unless it isn\'t an item or vehicle...');
}