Guys please give me some advice about that UsmMinFreqError thing. Is it a defect that I should worry about? Google shows only two results, and one of them directs to this very thread. HELPPPP! 
Hey there!
I'm an SX1 owner (and here within CHDK I'm the first "porter" for CHDK to SX1) and just wanted to confirm, that it may happen.
My 4years old S2 IS has this error too (when checking it with ver.req method). But since years, I had not the slightest problem! Actually last year on my Australia/NZ Trip i even dropped it on a hike around the "King's Canyon".... Luckierwise it fell onto the corner of the main LCD and this corner looks a little bit bumped, but still: It was a heavy drop onto Austrlian Rock. Nevertheless: the cam works still flawlessly (took another 3500 Pics on this trip)...
My 1 month old SX1 IS did not initially show this error. But last Saturday - when shooting a macro picture, I was getting to close to the objects and while touching by mistake the Zoom Controller, the Lens were blocked for a moment. I saw on the display shortly the message "Lens Error - Camera restart" and then the cam went out. After normally Power-on (retracting - extracting Lens) everything is normal.
HOWEVER: Since then I see the E18 - UsmMinFreqError also on my SX1 (including Time/Date stamp)...
Following assumption:
- Some errors are permanently logged/written into the Memory of the Cam (Like Firmware or the Settings of the "C" Mode or the Themes (Pictures/Sound) you can make/Upload for your cam). This memory area is NOT erased if a firmware update is made, neither can it be "reseted"...
- It is certainly possible to access/change this "internal error Log" as it is possible to upload a picture/sound with "My Camera Menu" Tool or "brand" your camera with your name/contact (shown in EXIF Informations later) - but unfortunately not without the right tool (Canon Service Tool/ Software - like Car-Companies have their Service-Systems in todays Car-Systems)...
I assume that Canon Service "uses" such evidence if servicing a Cam (even for other issues). OR blame the customer of having misused the cam ;-)
But also: Do not worry about the shown error in the "log" (eventough it would be nicer without)...under normal circumstances you will enjoy your Cam until End-of-Lifecycle....