Excel hangs up on first of 2 button scripts

This is for Excel 2008, OS X Snow Leopard, Applescript 2.1.2

I created two buttons on a sheet and assigned two script files to their “on action” property. The script assigned to the button created last is executed without problem. Excel hangs though when I press the button that is created first. If I switch the order I create the buttons, Excel again executes the last created button’s script but hangs on the first created button. Any ideas will be greatly appreciated.

Here is the code creating the buttons:

On createButtons()
set home to do shell script “echo $HOME”
tell application “Microsoft Excel”
activate object sheet 1
set a to “run script "” & home & “/Library/Scripts/Script1.scpt"”
set b to “run script "” & home & “/Library/Scripts/Script2.scpt"”
set buttA to make new button at active sheet with properties {caption:“A”,name:“A”,left position:0,top:10,width:150,height:50,on action:a}
set buttB to make new button at active sheet with properties {caption:“B”,name:“B”,left position:0,top:200,width:150,height:50,on action:b}
end tell
end createButtons