missing one or more ")" characters. Can't find where.

if(hostData){
for(var i:int = 0; i <hostData.length; i++){
if(GUI.Button(Rect(btnX 1.5 +btnW, btnY1.2 + (btnH * i), btnW3, btnH0.5), hostData*.gameName);*
Network.Connect(hostData*);*

First your curly braces are unbalanced, indent your code and that should be easier to fix.

Second, this line is has two major problems:

if(GUI.Button(Rect(btnX *1.5 +btnW, btnY*1.2 + (btnH * i), btnW*3, btnH*0.5), hostData*.gameName);*

- it is missing the closing bracket for the if statement.
- it should not end with a semicolon.
fixed:
if(GUI.Button(Rect(btnX 1.5 +btnW, btnY1.2 + (btnH * i), btnW3, btnH0.5), hostData*.gameName))*