Density profiles and first layer adsorption isotherms of a network forming fluid near a crystalline surface are investigated using the Percus-Yevick approximation for the associative Henderson-Abraham-Barker (HAB) equation. The fluid molecule is represented as a hard sphere with four independent attractive sites. The surface is described as a hard wall with a lattice of adsorbing sires. It is shown that the association induces a new type of cooperativity related to a bridging between the adsorbing sites due to tree-like clusters adsorption, The density profiles calculated exhibit reasonably good agreement with the Monte Carlo computer simulation data. The connectivity properties of the interface are studied and an interfacial percolation threshold is predicted to exist. The mean thickness tau of the adsorbed layer and the connectedness wall-particle correlation functions are calculated via the connectivity analogue of the HAB equation. It is shown that the adlayer may become infinitely thick with the mean cluster size S in the bulk being finite. (C) 1997 American Institute of Physics.