BigFish Game Wrapper - Calling DLL function

BigFish games wants to sell my game Xeno Assault but I have to use a wrapper program to put a 60 minute time limit on the game. For this I need to load a DLL, check for its existence and call a certain function within it every minute. I have done nothing with DLLs in blitz before - Is this even possible? If it is, how can it be done?

Here is the document they sent me - I know very little about C++ so I really don't know how this will work in Blitz:

Version with armodillo protection. You can easily
implement this 60 minute wrapper into your source code.  We have done this 
with many developers and will require 5 to 10 minutes of your time to 
implement.  The instructions to do this are as follows:
a) Call IncrementCounter() from ArmAccess.dll (attached to this email) once 
every minute from the game itself.
b) If ArmAccess.dll does not exist the game should not start
c) Provide us with a full version with this new code in a zip file for us 
to wrap

C++ code example

//In the main game procedure, on start-up
//*****************************************
//Declare the function
typedef bool (__stdcall *IncrementCounterFn)(void);
//Load the DLL
HINSTANCE libIncr=LoadLibrary("ArmAccess.DLL");  

//Get the function's address
IncrementCounterFn IncrementCounterFunction=(IncrementCounterFn)GetProcAddress(libIncr, "IncrementCounter");


//In the threaded (per-minute) function
//**************************************

//Read the Environment_Variables ALTUSERNAME value to check if a valid license was installed

//Note: During the Trial time, the license's user name is DEFAULT. A valid license key has a user name value that is different than
DEFAULT

GetEnvironmentVariable("ALTUSERNAME", name, 255);

If (!memcmp("DEFAULT", name,7))
{
        //exit the thread as a valid license key was installed
}

//Increment the per-minute counter by 1
ReturnValue=IncrementCounterFunction;

//Read the Environment_Variables EXPIRED value
GetEnvironmentVariable("EXPIRED", isExpired, 10);

//Check if the Trial license expired AND NO VALID KEY was installed
if(((memcmp("True",isExpired,4)) || (ReturnValue==0)))
        {
                //exit Game gracefully as the Trial license expired
        }

//In the main game procedure, on exit
//**************************************
//Free the loaded library
FreeLibrary;

Thanks in advance,
Neil