.net provider 2.90 version - figured it out (but still have problems)

GAC reports version 2.81 of the assembly but it is in fact 2.90. But I still have the following problem: When opening a great number of concurrent connections on a web site (around 2000 in my machine, but on other machines as few as 40) the .net provider (2.90) for informix just hangs. Using the previous version (2.81), it could hang or it could generate a fault and bring down the .net process. I did the following: created a c# project (class library) with a method that opens a connection, query a table, and closes the connection using 300 simultaneous threads. Then I created an aspx page that calls that method. Then with ACT simulated 10 concurrent requests to the page. .NET threads hangs even without really opening the connections to the database, and the only solution is to restart the .NET process. Using the ODBC provider, .NET correctly reports out of memory errors accesing the page, but after the threads finish, everything works fine again. Any ideas? TIA Mart'n.