Updating to add that we recently observed a problem on the computer of a user who was running Windows in English but with Devanagari numerals. Switching to Arabic numerals fixed his problem. I'll point out here that Bhutan (mentioned in my previous comment) speaks Dzongkha, which also has its own numeral system (which is often in base-20!).
This leads me to wonder if the issue here is due to foreign numeral scripts. In the one verified case where this was an issue, the problem was specifically caused by the foreign numerals being used in place of Arabic ones in package numbers, e.g. "42000DashingAI" would be presented to Java as "४२०००DashingAI", confusing the AEI. This could also theoretically occur in the level names, e.g. "level०_Final.dat", perhaps explaining why we have seen the AEI failing to recognize level files in cases of failed installation.
That being said, German and Russian use Arabic numerals, so I would guess that this is not just a numeral issue and that we may be seeing two similar malfunctions, one caused by foreign numerals and one caused by Unicode characters in directory names.
