fopen() of Windows file names containing spaces

[AileenRose]

Please help! I have a very frustrating problem which makes me feel dumb
since I am a newbie at this.

The script needs to open a file and remove a line based on a fed value.
  Basically it is a web button that calls:

removeline?c:/Program Files/user1/file.txt,line_that_will_be_removed

I take the argument before the comma separator and change the forward
slashes to back slashes.

I have gotten this to work from the command line in cygwin, modified it
to work from the command line in a cmd window.  Now, I have to make it
work as the executable that is called from a web page.

I have tried double backslashing, but it cannot open the file.
My file value is something like:

C:\\Program Files\\user1\\file.txt

When I look at my apache logs it shows the error of :
Cannot open file:  C:\\Program%20\\user1\\file.txt

Should I be taking care of the '%20' or is this just coming from the
fprintf?  How can I "scrub' the filename so that it works from the web?

Thanks!