Parameter ‘foobar’ not found in the collection. at MySql.Data.MySqlClient.MySqlParameterCollection.GetParameterFlexible
Does not mean what it says. It’s somehow related to a documented bug, and fortunately does have a fix. It can occur when arguments in ASP.NET to a MySQL stored procedure are specified in a differing order.
In ASP.NET when working with MySQL stored procedures, you MUST specify the parameters in the exact same order and upper/lower casing they appear in your stored procedure.
If this doesn’t fix it, you may have a problem with MySQL Stored Procedure Caching (how to fix). Symptoms here are that MySQL complains about wanting/missing parameters that you just deleted/added/updated being missing or too many.