AccessViolationException thrown when calling API function

I’m attempting to integrate an MC5728V Sierra wireless card for use on the Sprint network with a VB.Net application. My call to SwiApiStartup is successful and returns SWI_RCODE_OK as expected, but the next call to SwiGetAvailAirServers throws an AccessViolationException with the message “Attempted to read or write protected memory”. Any idea what might be going on and possibly how to get this working? I’ve attempted this integration with both VB.Net and C#. I’ve attached a simple C# example that demonstrates this issue. I’m attempting to use version 7.25.2.0 of SwiApiInterface.dll, SwiCardDetect.dll, and SwiApiMux.exe.
SierraWireless.Api.cs.txt.zip (1.13 KB)