[racket] Strange problem upgrading from 5.0.0 to 5.0.2

In an effort to solve my Geiser problem on Windows 7, I realized I
should update to 5.0.2 (from 5.0.0).

I ran the installer for 5.0.02 which did the uninstall of 5.0.0
followed by the install of 5.0.02.

Now on startup I get:

---
Error invoking tool #<path:C:\Program Files
(x86)\Racket\collects\gui-debugger>;("debug-tool.ss")

collects\gui-debugger\compiled\debug-tool_rkt.zo::0: read (compiled):
code compiled for version 5.0, not 5.0.2

 === context ===
standard-module-name-resolver
C:\Program Files (x86)\Racket\collects\drracket\private\tools.rkt:282:4
C:\Program Files (x86)\Racket\collects\racket\private\map.rkt:50:17: loop
C:\Program Files
(x86)\Racket\collects\drracket\private\tools.rkt:70:0:
load/invoke-all-tools
C:\Program Files (x86)\Racket\collects\drracket\tool-lib.rkt: [running body]
C:\Program Files (x86)\Racket\collects\drracket\drracket.rkt: [running body]
---

Here's the thing: I had manually tweaked debug-tool.rkt (to limit the
amount of text shown for each item in the values pane). IIRC, I had
run raco to rebuild, and it worked.

So I wasn't totally shocked by this error. I figured the uninstall
hadn't succeeded. So I did the uninstall, made sure that "Program
Files (x86)\Racket" was completely gone, and did the install all over
again.

And ... I'm still getting this error.  Huh??

I checked and the debug-tool.rkt file and the compiled/debug-tool.zo
and .dep files are all dated 11/ 06/2010. They are not the files I had
modified back in 5.0.0.

So ... what the heck is going on??