Apps not running correctly on phones from another country

Hello,

Two different apps I am developing at present are running just fine on 3rd Edition testing devices in Russia (N81-bought in the UK, 6290, N78 - bought in Russia), but these apps are not running on E63 or 6290 - bought in South Africa in one case, and in the other case - on two 3rd Editon testing devices bought in Norway.

Both apps are runnig on and not running on

3 devices in Russia 2 devices in South Africa and
2 devices in Norway.

All the devices are 3rd Edition Symbian.

What could be the reason for this? Network opertors (carriers)? Sim cards? Differences in hardware in phones produced for different countries?

Both apps in question deal with call recording/audio playback in the converstaion. (into the GSM line)

I really appreciate any advice on this.

Andrew

"Not running" is probably not enough to determine what's wrong.

Do they install properly on those devices without error messages? If not, what is the error message?

If they install, what happens when the app starts? Are any error messages shown? How does the app behave?

What language(s) has the app been localized to? Does it make a difference, if the phone language on those devices is set to "English"?

What are the firmware versions of both working and non-working devices? Can the non-working devices be updated to whatever is the latest version (if they're not at the latest version already)?

Can you make a "debugging" version for the problem users/devices, that they can install, and which will, e.g., write a debugging log for you to investigate (in case you don't have access to a device that doesn't work yourself)?

I would basically check whether you can also find a device from RDA from which you could repeat the problem, then it would be propably a lot easier to locate and fix.