Hi Erin,
Thanks for your response. But I frequently face above mentioned problem. I was living with it for past few months. Basically the probability of error is less when the search string is unique in some sense, like if i search for "product of two negative integers" with option "search in titles" the chances of getting "zero sized reply" is very less, as i think due to uniqueness of string, the search engine searches fast in comparison to when I give quite common string like "number properties".
May be you are sitting near to TM server that's why you may not be getting this error
