Ruby (Shoes) List box crash when populating from excel

I've got a problem when using Shoes. I'm basically trying to open an excel document and pass the names of the worksheets to a list_box. The following method is called on a button press after selecting a file. (This all works and the file opens)

exc = WIN32OLE::new('excel.Application')
excWB = exc.Workbooks.Open(xlsFile)
@excWS = Array::new
exc.visible = true
excWB.Worksheets.each { |ws| @excWS.push(ws.name) }
para @excWS
list_box :items=> @excWS  

Not only do the names not show up in the list_box, the app crashes shortly after loading the box with no error. para @excWS shows the nam开发者_如何学Goes of the worksheets with no problem.

What am I doing wrong?

---

it is the encoding that was the problem This works

Shoes.app :width => 400, :height => 340, :size => 8 do
  require 'win32ole'
  exc = WIN32OLE::new('excel.Application')
  excWB = exc.Workbooks.Open('C:/Shoes/0.r1514/test/book1.xls')
  @excWS = Array::new
  exc.visible = false
  excWB.Worksheets.each { |ws| @excWS.push(ws.name.force_encoding("UTF-8")) }
  list_box :items=> @excWS
  exc.ActiveWorkbook.Close(0);
  exc.Quit();
end