You likely will be able to skip this step. This step is for stock versions of Windows XP, which do not have dot NET installed. Try installing MySQL 5.5 first, then if you have problems, come back and perform this step
If you use these install instructions, please cite: Graham G.M. Alvare, Natalie K. Björklund, John Schellenberg, Richard Sparling, Brian Fristensky; Koala: Overlaying Local Gene Expression Data on BioCyc Pathway Diagrams