Help needed to fix these errors

[1master1]

These are the errors being generated when we access them.

First is openinviter error

Code:

Type: 2 File: front_end.php (Line no. 220) Message Cannot modify header information - headers already sent by (output started at /home/remosd/public_html/forum/inc/functions.php:92)

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  front_end.php (Size: 9.86 KB / Downloads: 532)

Next is with shoutbox and similarthreads plugins

Code:

File: inc/plugins/myshoutbox.php (Line no. 571) Message Cannot modify header information - headers already sent by (output started at /home/remosd/public_html/forum/inc/plugins/benzerkonu.php:139)

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  benzerkonu.php (Size: 7.3 KB / Downloads: 520)
  myshoutbox.php (Size: 55.37 KB / Downloads: 478)

Other error is with undodelete

Code:

File: inc/plugins/undodelete.php (Line no. 1043) Message array_walk() expects parameter 1 to be array, null given

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  undodelete.php (Size: 48.31 KB / Downloads: 505)

Cant figure out what causing the error. Any help is appreciated.