How can I use this package to reduce the CPU usage as I got the following line of code but I am unable to use it.

You canīt. Win32 is not magic wand you wave to reduce your CPU usage. You can, however, increase the efficiency of your code.
Please describe what you want to do with your logfile, and please provide some sample data.

And, please put <code></code>-tags around your code, to increase the chance that one will read it.

Update: code-tags have been added while writing this post.
Update: for linux/unix there is utility named "nice" that you can use to reduce cpu-load of a program. (with the price it will take longer to run).