updating custom_config.inc.php, TL will fails to run

[nariman]

I have TL installed on Ubuntu 11.x and it works fine until I touch the custom_config.inc.php. If I make any changes to this file (any), I get error 500 from going to: http://<ipaddress>/testlink/index.php

Any ideas?
I appreciate any help.

[fman]

additional blank lines AFTER ?> normally generate this issue.

[GunnarD]

And look in your webservers error_log, there can be som hint's whats going wrong, maybe you forgot ; at the end of a line.

[nariman]

maybe you forgot ; at the end of a line.

And sure that was it. Thanks