It appears from your code that you have line/paragraph breaks between each of the field sets. Instead of:
{ IF { MERGEFIELD FieldName1 } <> "" "<table><tr><td>ColName1</td><td>ColValue1</td></tr></table>" "" }¶
{ IF { MERGEFIELD FieldName2 } <> "" "<table><tr><td>ColName2</td><td>ColValue2</td></tr></table>" "" }¶
{ IF { MERGEFIELD FieldName3 } <> "" "<table><tr><td>ColName3</td><td>ColValue3</td></tr></table>" "" }¶
you should have:
{ IF { MERGEFIELD FieldName1 } <> "" "<table><tr><td>ColName1</td><td>ColValue1</td></tr></table>" "" }{ IF { MERGEFIELD FieldName2 } <> "" "¶
<table><tr><td>ColName2</td><td>ColValue2</td></tr></table>" "" }{ IF { MERGEFIELD FieldName3 } <> "" "¶
<table><tr><td>ColName3</td><td>ColValue3</td></tr></table>" "" }¶
where ¶ is your line/paragraph break.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]