I am currently running Selenium commands through PHPUnit to a remote server. I've run into a problem where I am trying to upload an image to an input form. 

In my PHPUnit, I have the command

```
$this->attachFile( 'file', 'file://test.png' );

```

My Selenium server returns an error

```
PHPUnit_Framework_Exception: Response from Selenium RC server for testComplete().
java.lang.RuntimeException: Output already exists: /tmp/selenium2070373138020433468upload.

```

My test.png file is currently only located in the folder where I am executing my .php unit tests from. 

How can I properly upload a file through PHPUnit and Selenium and get it to not throw an exception?