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Learn from the Errors!
Mostly, we can figure out the mistakes from
the type of error which the browser shows. Hopefully there is no
bug in the script itself. (Let us believe the script is well written
and has been checked in various environments). Here are some possible
major error messages which may occur:
1. Server: Error 500 or Internal server
error
You can get a server error 500 for many reasons,
some of which occur IF
†
the script does not contain the "#!/usr/local/bin/perl"
header line that points to the Perl interpreter, or if the path
to the interpreter (and/or a library file) is invalid.
† the first line output
from the script is not a valid HTTP header (i.e. "Content-type:
text/html"), or there is NO blank line after the header
data.
† there is a syntax
error in your script. Always run it from the command-line first.
† Check to make sure
that the ACTION="" of your script is pointing to the
correct CGI program. If it is, make sure that this file is also
chmoded 755 so that everyone, including the Web Server User
ID has permission to execute it.
†Make sure all files
to be opened during execution by the script are chmoded so that
the web server can read them
†Check all paths to
certain commands and make sure they are correct. An incorrect
path in your script will cause execution of your script to halt
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Check them and run the script again. I hope you've got it!
2. Error 403 "File Not Found"
Make sure that all of the URLs are correct
in the scripts and that when the necessary portions of certain URLs
are combined they form complete URL. Many do enter the URLs wrong
or do not change them from the standard distribution. You can avoid
this by double checking your entries.
3. Error 501 "Cannot POST to non-script
area..."
CGI scripts can be configured to run on most
systems in two ways, the first, inside a cgi-bin directory. Error
501 usually says that the server does not support the method POST
to a non script area. This means that since you do not have your
files in a server defined cgi-bin, the server will not allow the
POST method to these files, and will not execute these scripts.
Simply linking from your page to an executable program or script
won't cause it to be run on the server. There are two common arrangements:
either files in directories especially designated by the server
administrator are executed as CGI scripts, or files with a special
extension (such as .cgi) are executed as CGI scripts. Some times
you may need to rename PL files into .cgi to make the server understand
your script type, but this is very rare.
These are just two possible ways your server might be configured.
Many sites don't allow users to run CGI scripts at all. Consult
your web server's administrator and make sure that you have the
access for a cgi-bin..
4. "File Does Not Exist"
This error is generally caused by the wrong
path. Make sure that the path is to Perl. (Like " /usr/bin/perl")
Also make sure that the path in your HTML document is correct.
5. Cross-Browser compatibility
Some browsers are tolerant of incorrect Content-type
headers, as well as of null characters in text/html or text/plain
output. Make sure your output is strictly correct; it helps to check
the script with different browsers.
11. How
can I help you?
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