Just had a thought... I couldn't be running a wrong php version could I?
The server is is running version 5.4 with these settings:
Language Options asp_tags Allow ASP-style <% %> tags. Off
File Uploads file_uploads On
Paths and Directories include_path .:/usr/lib/php:/usr/local/lib/php
Resource Limits max_execution_time 120
Resource Limits max_input_time 120
Resource Limits memory_limit 200M
Data Handling register_globals Off
Language Options safe_mode Off
File Uploads upload_max_filesize . 20M
main session.save_path /tmp