Please bear with me, I'm new to XML. I loaded a huge amout of data into 40 different data islands on the same web page. I could transform the data in the first 25 data islands, but my style sheet returns nothing from transforming the 26th data island and beyond. Does IE6 have a data island limitation?

Not that I know of, it's probably a memory issue. Transforming that many islands on the client seems fraught with danger.
Can you show some of the transforming code so that we can see if you are using more memory than necessary? No need for all the page unless the islands are linked, with a src attribute, rather than embedded ones.

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Joe (Microsoft MVP - XML)