Database errors with MS SQL Server: Error establishing socket

Various users have reported (eg. http://forums.atlassian.com/thread.jspa?messageID=257216865곴?) getting intermittent errors with the MS JDBC driver:

Exception reindexing: com.atlassian.jira.issue.index.IndexException:
Error: com.atlassian.jira.exception.DataAccessException:
org.ofbiz.core.entity.GenericDataSourceException: Unable to esablish a
connection with the database. ([Microsoft][SQLServer 2000 Driver for
JDBC]Error establishing socket.)

or:

• javax.servlet.error.message : Unable to esablish a connection with the database. ([Microsoft][SQLServer 2000 Driver for JDBC]Error establishing socket.)<p><small><small><pre>com.opensymphony.module.propertyset.PropertyImplementationException: Unable to esablish a connection with the database. ([Microsoft][SQLServer 2000 Driver for JDBC]Error establishing socket.) at com.opensymphony.module.propertyset.ofbiz.OFBizPropertySet.findPropertyEntry(OFBizPropertySet.java:231) at com.opensymphony.module.propertyset.ofbiz.OFBizPropertySet.setImpl(OFBizPropertySet.java:167) at com.opensymphony.module.propertyset.AbstractPropertySet.set(AbstractPropertySet.java:570) at com.opensymphony.module.propertyset.AbstractPropertySet.setString(AbstractPropertySet.java:368) at com.atlassian.jira.propertyset.JiraCachingPropertySet.setString(JiraCachingPropertySet.java:317) at com.atlassian.jira.config.properties.ApplicationPropertiesImpl.setString(ApplicationPropertiesImpl.java:120) at com.atlassian.jira.web.action.setup.Setup.setLanguage(Setup.java:111) at com.atlassian.jira.web.action.setup.Setup.doDefault(Setup.java:58) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:324) at webwork.util.InjectionUtils$DefaultInjectionImpl.invoke(InjectionUtils.java:61) at webwork.util.InjectionUtils.invoke(InjectionUtils.java:52) at webwork.action.ActionSupport.invokeCommand(ActionSupport.java:417) at webwork.action.ActionSupport.execute(ActionSupport.java:146) at com.atlassian.jira.action.JiraActionSupport.execute(JiraActionSupport.java:46) at webwork.dispatcher.GenericDispatcher.executeAction(GenericDispatcher.java:131) at com.atlassian.jira.web.dispatcher.JiraServletDispatcher.service(JiraServletDispatcher.java:186) at javax.servlet.http.HttpServlet.service(HttpServlet.jav