Jon,
1. WCA can fail when we search for ONE term on the very first use of WCA for that day.
Or it can occasionally work for several runs, where each run might be 1-3 terms
Then up comes one of the error msgs.
2. My install on my Win7 machine is set to run as administrator, in case that matters. I think we went this way after it wasnt working without 'run as admin'. On my wife's machine, I think we also run as admin.
3. When my wife is using WCA (but both of us do not use it at the same time - not even in the same hour) she often get the Oman results. (I dont.) She sees a sometimes pattern of getting the Oman results during America's sleeping time, 10pm East Coast till early morning (our day here in Australia).
4. Yes, we've concluded that Yahoo dont like to be interrogated too often. But when we resort to manual Google searches, using the SEOquake plugin, we sometimes get the red error where the LD (link domain) stats should be... on the first page of Google search results. In other words, before we've hit Yahoo "too often over the last hour".
5. While writing this for you, I ran WCA.
First run - 1 keyword - worked fine.
Second run - 3 - fine.
Third run - 6 - half way through the last term it started producing BL=0 and SL=0 results.
If it performed this well every time, we'd be smiling. But alas, the points above are our usual experience.
Gary
PS: Jon, may I be so bold as to suggest that you do your public image a favour when you see a customer asking for your help... by at least writing a note saying you've seen their post. Silence is not always golden.