Upgrading JIRA from 2.4 to 3.1

I am attemting upgrade from 2.4.1 to 3.1.0 version of Jira.
I got application up and running under new version and using Integrity Checker I was able to resolve most of my potential problems but I still have few problems:

When I go to browse projects under project summary I have Open; Closed and Blank issues (blank one is throwing exceptions in the log

2005-02-21 13:10:08,234 ERROR [webwork.util.ServletValueStack] METHOD: "", exception:
java.lang.NullPointerException
at webwork.util.ValueStack.findMethod(ValueStack.java:747)
at webwork.util.ValueStack.findValue(ValueStack.java:391)
at webwork.util.SimpleTest.test(SimpleTest.java:391)
at webwork.util.ValueStack.test(ValueStack.java:132)
at webwork.view.taglib.IfTag.doStartTag(IfTag.java:38)
at jsp._includes._panels._browser._openissuesjsp._jspService(_openissues_jsp.java:131)

I traced part of the problem to issuestatus #2 (Assigned) in jiraissues that I had and new Jira doesn't. I changed all issuestatus items with value 2 to value 1 but I am still seeing same problem.

I am also seeing this error at startup
2005-02-21 13:04:38,734 WARN [atlassian.jira.upgrade.ConsistencyCheckImpl] File entityengine.xml is configured to use 'mssql' but there is no known mapping to database 'Microsoft SQL Server' or 'SQLServer

thanks
vlad