continuously getting 'Object cannot be found or 'object has been deleted'

Totally new using TestComplete. Using Keyword tests with simple cases. Running the test  individual test cases work one minute and then the next I get 'Object cannot be found' or 'Object has been deleted'.  I found the information on setting the wait time to a longer period but that isn't working either.  I am using Chrome and configured it according to the quide lines.  Any ideas what else can try. Basically the keyword tests will work and then they stop working