"Ergodic" is being used here to mean literature where "nontrivial effort is required to allow the reader to traverse the text".
In other words, literature where the reader is either encouraged or forced to actively participate in the progress of the text. In The Unfortunates, famously, the 'novel' is a sheaf of 32 sections in a box. The reader is instructed to shuffle them into any order desired before reading. I've never seen Landscape Painted with Tea, but Pavic's prior novel, The Dictionary of the Khazars, is presented as a set of encyclopaediae, with readers encouraged to follow the cross-references as fancy takes them.
–more at Playing ergodic literature