I have a problem with Apache running on a Linux server. This error undefined index on PHP, for example.

The problem is that my Apache server doesn't log entire error messages. Some lines from the error.log file:

[Thu Nov 29 05:29:06 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undefined index:  lin
[Thu Nov 29 05:29:06 2012] [warn] mod_fcgid: stderr: 9
[Thu Nov 29 05:31:30 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undefined index:      link in /var/www/html/sit
[Thu Nov 29 06:01:18 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undefined index:  link in /var
[Thu Nov 29 06:06:09 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undefined
[Thu Nov 29 06:06:15 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undefined index:
[Thu Nov 29 06:13:04 2012] [warn] mod_fcgid: stderr: PH
[Thu Nov 29 07:14:16 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undef
[Thu Nov 29 07:32:16 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undefined index:  link in /var/www/ht
[Thu Nov 29 07:34:26 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undefined index:  link
[Thu Nov 29 07:34:30 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undefined index:  link in /var/www/html/site.com/
[Thu Nov 29 07:41:10 2012] [warn] mod_fcgid: stderr: PHP Notice:  Und
[Thu Nov 29 07:41:11 2012] [warn] mod_fcgid: stderr: PHP Notice:  Und
[Thu Nov 29 07:41:12 2012] [warn] mod_fcgid: stderr: PHP Notice:  Und
[Thu Nov 29 08:14:20 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undef
[Thu Nov 29 12:36:54 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undefined index:  li
[Thu Nov 29 12:37:04 2012] [warn] mod_fcgid: stderr: PHP Notice:  Unde
[Thu Nov 29 12:46:52 2012] [warn] mod_fcgid: stderr: PHP Notice:  Undefined index:  link in /var/www/htm
[Thu Nov 29 13:00:33 2012] [warn] mod_fcgid: stderr: line 35
[Thu Nov 29 13:10:55 2012] [error] [client XXX.XX.XX.XX] File does not exist: /var/www/h

Some lines are incomplete and truncate the error message.

Anyone know Why Apache is saving incomplete error messages?