Our app is composed of a Flex front-end and a .NET web service. The .NET web service does all of the querying from the salesforce API, processes some of the returned queries, and then passes it back to the Flex app for presentation/use.

Recently we've noticed a strange error that is disruptive and occurs inconsistently:

1. We will be querying for data related to opportunities, accounts, tasks and the like. The queries will be returning back results just fine.

2. All of a sudden, one of the queries will return with an error such as INVALID_FIELD, INVALID_QUERY_LOCATOR, INVALID_SESSION_ID, INVALID_TYPE, MALFORMED_QUERY. The errors about fields and malformed/invalid query will usually state that an invalid column, object, or unsupported call like convertCurrency doesn’t exist for the org - even though it does. Yes - we can be querying data from an organization using multi-currency, and all of a sudden one of the queries will say that multi-currency is not supported for that org.

3. We can then re-run the same query that failed, and sometimes it will work immediately. Other times, it will fail for a few minutes, and then start working again.

Could it be something to do with the fact that multiple users from many different companies are using our app concurrently, and even though they each have unique session parameters, the fact that they`re all appearing to come from the same IP (our server) is causing some to collide and fail.

Right now, we`re stumped and hoping someone can point us in the right direction.