I'm using "Informix Client SDK 4.10" to make an application in Visual Studio 2010 asp.net vb.net.
To query the database I use the following code:

Dim ds As New DataSet()
Dim str_sql As String = ""
str_sql = "select * from prova order by id"
Dim da As New IfxDataAdapter(str_sql, conn_ifx)
da.MissingSchemaAction = MissingSchemaAction.[Error]
da.FillSchema(ds, SchemaType.Source, nome_tabella)
da.Fill(ds, nome_tabella)
The code works correctly if in the table there are no decimal type fields.
but if in the table there are the decimal type fields then I get the following error:

input string format not valid
I point out that:
Client_Locale = en_US.819; DB_LOCALE = en_US.819
and informix cli is Italian version.
It may depend on the setting of the culture?