Hi Anthony,
I have excluded zero impression by setting IncludeZeroImpressions to False in HTTP header.
IsNegative and KeywordId fields do not support zero impressions. But as stated in documentation, "Zero impression rows are implicitly excluded when a report request contains any field that does not support zero impressions.".
So, with these fields also, report behavior will be same.
After removing fields KeywordId,Date,AdNetworkType2,IsNegative; I am getting paused campaign (as given in private message), which has data for columns - Pages / visit and Avg. visit duration (seconds).
So Do you have any idea why this row is getting excluded?