The buildomatic installer does an validateHost check in validation.xml.
This calls the ant <isreachable> task which in turn calls the Java InetAddress.isReachable method.
What this does is check that host is reachable by doing an ICMP ping and echo operation.
If for some reason this fails then the installation fails even though the database itself is completely accessible.
We have had this happen ourselves and have had to disable the failing of the validation to get the jasper server application to install.