operator not supported for strings on line

[Barzor]

I recently migrated to another server. No problems untill..
I suddenly get this error when I try to see a thread. Can somebody explain what this means?

[] operator not supported for strings on line 37 in /home/w12sdmo3osve/public_html/vb/ckeditor.php(74) : eval()'d code
#0 /home/w12sdmo3osve/public_html/vb/ckeditor.php(74): eval()
#1 /home/w12sdmo3osve/public_html/vb/ckeditor.php(44): vB_Ckeditor->__construct('qr', 'vBForum_Post', 0, 29, '1', '2')
#2 /home/w12sdmo3osve/public_html/includes/functions_editor.php(500): vB_Ckeditor::getInstance('vB_Editor_QR', 'qr', 'vBForum_Post', 0, 29, '1', '2')
#3 /home/w12sdmo3osve/public_html/showthread.php(2058): construct_edit_toolbar('', 0, 4, 1, 1, false, 'qr', '', Array, 'forum', 'vBForum_Post', 0, 29)
#4 {main}