The problem is raised when a model object has a numeric (Decimal) field. The insert sql clause (on save) does not translate correctly the unicode original value to fixed float datatype.

For some datatypes, is needed to do some translation from unicode object type to specific firebird type required by kinterbasdb.

Look at: http://kinterbasdb.sourceforge.net/dist_docs/usage.html#adv_param_conv_dynamic_type_translation

Maxi,

how does numeric/decimal fields relate to Unicode?

I think what it was solve in trunk on new type conv implementation. Sure, we need test it deeply.