Server error

[#1]

I am getting the following error when submitting forms on my web site:-
Server error!
The server encountered an internal error and was unable to complete your request.
Error message:
Premature end of script headers: formmail.pl
If you think this is a server error, please contact the webmaster.
Error 500
ccgi.beilby.plus.com
Tue Mar 16 10:27:21 2010
Apache

After making a very simple change to the formmail script (correcting a telephone number) I got the error. I have now reverted to the original file ( > 2 years old) and still get the same error message.
Anyone got any ideas on what could be wrong please.
Regards,
Richard Beilby.

[#2]

Hi Richard,
Have a read of this and check what you have in your .htaccess files.

[#3]

Thanks, Bob. I have checked after reading the post and found that the perl script file (pl) did not have the execute permission set. I now have it set to read and execute for all users plus write for the owner. I presume these setting are correct. 
Regards,
Richard Beilby.

[#4]

Quote from: beilby

I now have it set to read and execute for all users plus write for the owner. I presume these setting are correct.

Just 700 for scripts. See <a href="http://community.plus.net/forum/index.php/topic,84349.0.html"> this post</a>.
Gabe