Another cause of this error could be an attempt to use the string "open" as a bareword-string in some context that the interpreter can't make a clean assumption about.

For example, when writing quick and dirty code using the CGI module and forms, I sometimes get that warning for the keyword, "values". Several of the form widgets like listbox, etc., have a parameter called "-values" that can be mistaken for a - followed by values, and expecting a hash following that.

You may have a similar situation in your code.

--rjray