Question: I have a web application which i am hosting. It is working fine on my machine and most machines i try on.

My client is saying the functionality of the web application is working fine. However, it takes ages for the site to load on his machine and if he presses a button the site takes ages to process things. He has also said he has tried the site on another machine and gotten the same issue.

How can i test what is the issue on the clients machine?

Answer: 
Check your `php.ini` and see if the function that you are using to run the programs have been disabled by the `disable_functions` setting e.g.

```
disable_functions=exec,shell_exec,system,proc_open ... 

```

If the function you are using is listed, remove it.

EDIT: from the comments the solution was to set 

```
safe_mode=off

```

in php.ini.
By editing php.ini, you are disabling safe\_mode server wide. Actually, you have the option in your plesk itself under Plesk >> Domains >> Domain Name >> WebHosting Settings section to disable safe mode for particular domain. This will keep the master value to "On" and Local value to "Off" for the particular domain.