Upgrade error with postgres driver

Hi all,

I had a 5.0 TeamCity installation and I upgraded it to 5.1.2 by simply replacing the TeamCity folder with new one and changing database.properties files to match new example.

However this is the problem I am getting when going to TeamCity page:

Error on step: Waiting for a database server...
Database driver not found:
Unexpected error calling  DriverManager.getDriver("jdbc:postgresql://localhost:5432/teamcity"): No  suitable driver
SQL exception: No suitable driver

Database is certanly up and running, so not really sure what that can be.

Any sugestion how to fix greatly appreciated!

Thanks.

PS Below is config file

connectionUrl=jdbc:postgresql://localhost:5432/teamcity
connectionProperties.user=[username]
connectionProperties.password=[password]
maxConnections=50
testOnBorrow=false