Hi friend!
First of all answering your question with one question
Do you have a sub-folder called arq_sql?
If you don't have, try to creat it and run again.
And the second, I am making a new Framework very simple to use and with a lot of things.
Isn't finished yet but you can see here
github.com/helhoso/phpFrameWorkClas
...
If you need any more information call me on hflb01@gmail.com