Can you attach a database trace log file here? With that it's maybe possible to find the reason for that error message.
I found the answer to this issue when requesting a support incident with Landesk through the portal.
Essentially, the problem was that I had added criteria to the default query that the system didn't like causing it to attempt and display a reminder on the window with a duplicate serial number. I had to remove the criteria and then create a filter that did the same thing as a window query and remove the default reminders collection from the window. Everything worked after that.