There are a few requirements your system needs to meet to be able to use CSVI VirtueMart. The requirements are:

• PHP version 5.2 or higher
• MySQL version 5 or higher
• Apache 1.3 or higher
• Joomla 1.5.14 or higher
  
• VirtueMart 1.0.x or VirtueMart 1.1.x
• GD 2.0 library if you want to automatic resize thumbnails
• Magic Quotes turned off

In case your system does not meet any of the requirements you will need to upgrade to the minimum version to be able to use CSVI VirtueMart.