After searching for and finding a contact and opening it's page, clicking on Activities, the activities are listed on the page, but the "Contact" field for each Activity is empty.
At first we were able to modify Activities and re-assign them, however the Contact field was always set to "None" when someone tried to modify the activity. After the activity was modified, Contact field changed to the correct name and then saved, it again appeard without contact associated with it.
Now we can't even edit the Activity, modify it or complete it. Get the error message pasted below.

What can cause this?

Thanks in advance for any advice.

~~~~~~~~~~~~~~~~~~~~~~~
The actual error is:

java.sql.SQLException: Contact ID not specified.
at org.aspcfs.modules.contacts.base.Contact.queryRecord(Unknown Source)
at org.aspcfs.modules.contacts.base.Contact.(Unknown Source)
at org.aspcfs.modules.contacts.actions.ExternalContactsCalls.executeCommandDetails(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java(Compiled Code))
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java(Compiled Code))
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java(Compiled Code))
at java.lang.reflect.Method.invoke(Method.java(Compiled Code))
at com.darkhorseventures.framework.servlets.ControllerServlet.service(Unknown Source)
at javax.servlet.http.HttpServlet.service(HttpServlet.java(Compiled Code))
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java(Compiled Code))
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java(Compiled Code))
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java(Compiled Code))
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:870)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:685)
at java.lang.Thread.run(Thread.java:567)