Hi Simon
I just looked at the binary in \Applications\uTaskerV1.4\GNU_AVR32uTaskerV1.4.bin and it is 16k in size.
Compared to a binary in my working project directory, 58k in size, it does seem to be a very stripped down version and so I suggest loading the reference on the SW demo page:
http://www.utasker.com/SW_Demos.html#AVR32_EVK1105 (I just updated this so that it includes the standard web support and also allows bit maps to be copied to the display on the board). This should ensure that you have a correct reference.
As to the simulator problems - I have never heard of PCs only partly working before. Either there is a problem that the NIC is not correctly configured (and nothing works) or it is correct and then it is reliable. Can you make some recordings (use one PC connected to a network with nothing else connected to it - just the PC to a switch or hub, etc., which is adequate for the simulator to run). The ping the simulated device from the same PC and record what happens using WireShark. It should give 100% ping answers - if not some investigation will be required.
Regards
Mark