Assamese doesn't have plural information in Zanata and thus cannot be added to a Zanata instance. Furthermore, existing instances that already have translations for Assamesse could fail while pushing/pulling translations.
Added Assamesse plural form to Zanata. Also added a default plural form so that locales can be added to zanata when Zanata does not hold specific plural form information. This default is basically no plurals allowed, which can be overridden by supplying the information on a POT file when pushing. See: http://github.com/zanata/zanata/commit/49ce2a7f68690138aa2c124b6a5ebf0cc40ad9dc
Added warning when adding a locale for which no plural information can be found. See: http://github.com/zanata/zanata/commit/7b992e7a36110a321e41b5902de4e5d5e52e3013
VERIFIED with Zanata version 1.6.1-SNAPSHOT (20120702-0014) Zanata version 1.7-SNAPSHOT (20120702-0025)