Requests not being generated.

Using loadui 2.0.0 I've created a simple ramp up load test with a soapui runner. But whenever I run it, the expected number of requests aren't generated. For example the last test I did was supposed to ramp up from 0 - 100 over 5 mins. This should have given a total of 15k requests. But it never got beyond 3.5k according to the soapui runner, even though the ramp generator kept climbing to 100.
When I looked at the stats module the line representing the requests/s just stopped at a certain point part way through the test??

Also, as a side issue, whenever I abort running requests, this seems to take an absolute age. And even when nothing is running the 'aborting running requests' message is still displayed.