I just had the same problem. The 1.0.05.12140 firmware update is for EU models only. I thought that I had a PRS-T2/EU but it turns out that it's a US one.
Look in Settings, Application Preferences, Dictionary. If you only have English, Spanish & French dictionaries you are probably running with US firmware. You could also check in Settings, General Settings, Country/Region. If the choice is only United States or Canada this is a US reader.
The US & EU types are hard-coded and you can tell by using this procedure from Shark69's rooting instructions which one you have.
Connect the Reader to your PC and run these from a command prompt:
USA
. \ Ebook_msc.exe name PRS-T2/2001 getdrv
EUROPE
. \ Ebook_msc.exe name PRS-T2/2044 getdrv
When your command responds with a letter, this is yours. If the response is NONE, that is not your model.
My guess is, the first command will give you a letter, meaning your device is US and so the latest firmware update cannot be applied.