I have the identical problem as the OP - I downloaded LoadUIWeb yesterday and launched into my first (very simple, login/logout) test. There are no external dependencies (like the Excel post mentioned). After about 25+ VU's are set to a test (add 1 VU per Second), there's a good chance that the test will not complete without manual stopping. I can't produce anything more repeatable than that and I am not (yet!) familiar enough with the reporting structure to ferret out any tell-tale problems. Any insight would be appreciated as my team and I are trying to make a decision as to what load-testing product to use on our project and Load UIWeb seems (seemed?) to have a lot of good things going for it (assuming I can simulate more than 20 virtual users in a single test).
Example of one of many similar Errors in Logs (99 VUs): Iteration 1 of the scenario "Login_Logout Scenario" assigned to the virtual user "Virtual user group (72)". Connection 5 was simulated partially. Only 7 of 29 requests were simulated. The execution was terminated by the user. 9/24/2014 11:30:31 AM
The last part of this error appears to be explicitly tied to the fact that I stopped it - but does the preceeding text give anyone any further indication of what's going on?