Surface coating script

Hi,
 
I am running a script to coat the surface of a ZnO nanocluster with oleic acid (OLA.xsd) molecules. But I am getting an error :
 
The index value 0 is out of range (function/property "Linkages") at -e line 58. 
 
Since oleic acid is a large molecule it goes inside the nanocluster!
 
Is there a solution to avoid this problem?