File::ALT_SEPARATOR nil

[andreasronge]

In the .../1.8/gems/ruby-graphviz-0.9.6/lib/graphviz.rb method escape_path_containing_blanks
line 714
def escape_path_containing_blanks(path)
path.gsub!(File::ALT_SEPARATOR, File::SEPARATOR)
throws an Exception on my machine since File::ALT_SEPARATOR
A simple workaround is:
def escape_path_containing_blanks(path)
path.gsub!(File::ALT_SEPARATOR, File::SEPARATOR) if File::ALT_SEPARATOR

I'm using ubuntu 9.10, JRuby 1.4.0