We have a Joomla based website (Joomla v1.0.11 with Virtuemart v1.0.7) that is already available and it needs to be upgraded to Joomla 1.5 (with VirtueMart 1.1.4). We tried the steps mentioned at the URL - http://forum.joomla.org/viewtopic.php?f=430&t=419087&p=1770173
to upgrade, however it fails to upgrade VirtueMart. There seems to be an issue with the ETL plugin and hence results in install errors.
If anyone has done a similar up-gradation, please mention the steps followed.