I am getting glibc errors

[Ovidiu]

I do not know anything about this, so I`ll post some lines from my logfiles:

Nov 22 14:05:08 hxxxx proftpd[1213]: hxxxx.serverkompetenz.net
(218.234.13.xxx[218.234.13.xxx]) - USER web: no such user found from 218.234.13.xxx
[218.234.13.xxx] to 81.169.xxx.xxx:21
Nov 22 14:05:08 hxxxx *** glibc detected *** corrupted double-linked list:
0x081102a0 ***
Nov 22 14:05:08 hxxxx proftpd[1235]: hxxxx.serverkompetenz.net

Nov 22 14:05:11 hxxxx proftpd[1252]: hxxxx.serverkompetenz.net
(218.234.13.xxx[218.234.13.xxx]) - no such user 'web'
Nov 22 14:05:11 hxxxx *** glibc detected *** free(): invalid next size (fast):
0x08110270 ***
Nov 22 14:05:11 hxxxx proftpd[1251]: hxxxx.serverkompetenz.net

Nov 23 00:28:40 hxxxx *** glibc detected *** malloc(): memory corruption: 0x081118b0
***

Any idea how to track this error down and remove?