unable to deploy on Openshift platform

Have choosen MySQL DB, have tryed both Tomcat's JNDI resource and jdbc type of connection.
The following error occurs in log:
java.lang.IllegalStateException: Roller Weblogger has not been prepared yet
        at org.apache.roller.weblogger.business.startup.WebloggerStartup.getDatabaseProvider(WebloggerStartup.java:64)
        at org.apache.roller.weblogger.business.startup.WebloggerStartup.getDatabaseInstaller(WebloggerStartup.java:155)
        at org.apache.roller.weblogger.business.startup.WebloggerStartup.isDatabaseCreationRequired(WebloggerStartup.java:95)
        at org.apache.roller.weblogger.ui.struts2.core.Install.execute(Install.java:85)

As I understand from 'Install.java' class, the error expected to occure several lines earlier, namely in 'Install.java:71':
        if (WebloggerStartup.getDatabaseProviderException() != null) {
where presence of exception checked. But if doesn't occur, hence, there is no exception.
The exception expected to be assigned at 'org.apache.roller.weblogger.business.startup.WebloggerStartup#prepare' method.
So I conclude this method was never called.