I have written a module to display images on my site, but I'm getting the following error on the site:

```
Fatal error: Can't use method return value in write context in /public_html/camps/modules/mod_slider/mod_slider.php on line 24

```

This is what is showing on line 24:

```
<?php if (!empty($params->get('image-1')) || !empty($params->get('image-1-alt')) || !empty($params->get('image-1-caption'))) { ?>

```

Any ideas what's gone wrong?

The server is running PHP version 5.3.10-1ubuntu3.15