VisualStudio changes to vb code seem to be ignored

My site is http://www.arithmequick.com . It has opened fine for years like this:
 [1] It opens with index.aspx
 [2] index.aspx opens AQ.swf
 [3] AQ.swf loads my games by calling http://www.arithmequick.com/TestLoadVars.aspx passing the parameters ActionType=LoadSTopicsForGames & CategoryIndex=0
 [4] In this call to TestLoadVars.aspx, its code-behind, TestLoadVars.aspx.vb, enters a Select Case ActionType and goes to the Case "LoadSTopicsForGames", which loads the games and the program runs fine.
 Now, using FTP mode in VisualStudio 2010, in TestLoadVars.aspx.vb, I added Case "LoadChallengeLevels" and I added this to the opening:
 [5] AQ.swf tries to also load my challenge levels by calling http://www.arithmequick.com/TestLoadVars.aspx passing the parameter ActionType=LoadChallengeLevels
 In response, I get Error #2101.
In an attempt to find the problem, I changed the code in Case "LoadChallengeLevels" to be simply:
Try
Response.Write("challengeLevelStr=Try")
Catch x As Exception
Response.Write("challengeLevelStr=Catch")
End Try
Again,  in response, I get Error #2101.
In fact, if I run http://www.arithmequick.com/TestLoadVars.aspx?ActionType=LoadSTopicsForGames&CategoryIndex=0, I get
gameStr=(a long list as expected).
However, if I run http://www.arithmequick.com/TestLoadVars.aspx?ActionType=LoadChallengeLevels, I get a blank screen, instead of challengeLevelStr=Try or challengeLevelStr=Catch.