i have a cgi reading a post cgi['search']

the value is the name of file which might exists under "/path/to"

because i'm a newbie with cgi, i want to print only if the file exist or
not :

file="/Users/yt/man/#{cgi['search']}.html"
print "FileTest.exist?('#{file}') = "   # here i get the right file name
print FileTest.exist?(file)   # here i get Internal server error why ???

this is strange to me because if i print :

print FileTest.exist?("/Users/yt/man/eruby.html") #without variable

i get true, without internal server error...

even if i define :
def file_exist(file)
  Dir.glob("/Users/yt/man/*.html").each do | _file |
    return true if _file===file
  end
  return false
end

and print :

print file_exist(file) # NO Internal Server Error

any light ?

in the mean time i had a look upon the server error log, giving :
[Wed Apr 30 19:03:19 2008] [error] mod_ruby: error in ruby
[Wed Apr 30 19:03:19 2008] [error] mod_ruby:
/Users/yt/Sites/ruby/man-receive.rbx:54:in `exist?': Insecure operation
- exist? (SecurityError)

the cgi isn't accessible externaly...
-- 
Une Bue