The warning string %s' has mandatory options '%s' and none is selected does not pick up translation strings for plan names. In our case it shows as:

Chosen plans combination is not allowed (you must choose coherent plans selection, e.g. mandatory subscription(s) must be active or mandatory plan(s) must be chosen). '_UE_SINGLE' has mandatory options '_UE_IMMEDIATELY', '_UE_SUB_TWO_WEEKS', '_UE_SUB_MONTH', '_UE_SUB_TWO_MONTHS', '_UE_SUB_THREE_MONTHS', '_UE_SUB_SIX_MONTHS' and none is selected.

These text definitions show up correctly in every other step of the subscription process, but not in the case where this warning is generated.

We are using CBSubs 3.0, CB 1.9 and Joomla 2.5.9. We have 2 languages: en-GB and ja-JP

These are the text strings we have created:

"_UE_SINGLE" => "Single Adult Membership (16 years and older)",
"_UE_IMMEDIATELY" => "Start WWoofing immediately",
"_UE_SUB_TWO_WEEKS" => "Start in 2 Weeks",
"_UE_SUB_MONTH" => "Start in 1 Month",
"_UE_SUB_TWO_MONTHS" => "Start in 2 Months",
"_UE_SUB_THREE_MONTHS" => "Start in 3 Months",
"_UE_SUB_SIX_MONTHS" => "Start in 6 Months",

They are translating at every step in the CBSubs process (payslips, invoices, auto mails, etc.). The only place they are not being translated is in the warning message that appears if you click submit without choosing an appropriate sub option (child plan?) at registration. At that time the message appears as included in my original post.

Thank you for your advice but I think there is a bug.

The part of the system that issues a warning if you submit a form without selecting all payment plan options that are required is ignoring the translation files. It only shows in the warning window whatever you have put into the input boxes in CBSubs, not the alternate definitions for that string from the translation files. Whatever I type in the input box "Name of plan" under CB Paid Subscriptions: Plans --> Presentation is what comes out in this warning message on screen, NOT what I have put into my definition files (not for any language). I DID change the definition files as you recommended.

Also, the other text strings in this warning message do not change, even if I modify them in the language configuration files:
"Chosen plans combination is not allowed (you must choose coherent plans selection, e.g. mandatory subscription(s) must be active or mandatory plan(s) must be chosen." =>

"'%s' has mandatory options '%s' and none is selected." =>