Symptom:
In release 4.8(1) ES1 (i.e. "4.8(1.0.1)"), IDC is unable to run in non-English mode.  

On the PC,  the "C:\Program Files (x86)\Cisco Systems\CISCO IDC 4.8\4.8\Bin\ja-JP" folder does NOT exist.
This suggests IDC is unable to download the language pack from the server.  

Using WireShark, we see IDC is trying to download the language pack from the wrong URL:
  ... HTTP      160          GET /ipics_server/language-packs/idc//ja-JP.zip HTTP/1.1
Note the '//' where the IDC version should be.

Conditions:
IDC 4.8(1) ES1 (i.e. "4.8(1.0.1)")
Windows OS is running in non-English locale.