Why would Part::partw appear in DSolve expression in Mathematica

I am trying to solve an differential equation:

DSolve[{0.02*x^2*y''[x] - y'[x] - y[x] == 0}, y[x], x]

But I got warnings:

Part::partw: Part 2 of {1} does not exist.

How do I underst开发者_运维知识库and this warning? Many thanks.

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I can reproduce this in V7.0.1, but not in V8.0.1, so it looks like a bug that got fixed at some point. The ultimate answers in both versions are the same.