Undefined property - $delta and $module

I get also an undefined property error - not $language but $delta and $module:

Notice: Undefined property: stdClass::$delta in _linkchecker_add_block_custom_links() (Zeile 876 von .../sites/all/modules/linkchecker/linkchecker.module).
Notice: Undefined property: stdClass::$module in _linkchecker_add_block_custom_links() (Zeile 876 von .../sites/all/modules/linkchecker/linkchecker.module).

I get no errors, if I disable the "browse blocks by links" option in the configuration. I do not know if it matters, but I use the module nodesinblock.