error when i try to bot in gld2_gef in xkore2

[lulu1148]

error when i try to bot in gld2_gef in xkore2, its hall of abyss
this is the error:

Error message:
Can't call method "isWalkable" on an undefined value at src/Interface/Wx.pm line 1296.

Stack trace:
Can't call method "isWalkable" on an undefined value at src/Interface/Wx.pm line 1296.
at src/Interface/Wx.pm line 161
Interface::Wx::mainLoop('Interface::Wx=HASH(0x5856ad4)') called at openkore.pl line 97
main::__start() called at start.pl line 136

Died at this line:

* $walkable = $field->isWalkable($x, $y);
if ($x >= 0 && $y >= 0 && $walkable) {

can someone help me?