VB6 activex dll makes the client wait when one call is executed

Hi All,
To start with, any help will be really appreciated as i have been dealing with this issue for quiet a long time and still i could not find a solution.

Plot:
I am using an activex dll for executing certain functionalities in my project. The dll has got a function 'GetResult' which returns a particular result.
I am calling this dll from my client(multithreaded) which is an activex exe in c++ .
I imported the dll into the project and then using CoCreateInstance created the instance of the module and calls the function . Everything works fine and the return comes too but the problem is that when one thread in my client calls the dll function for getting result it holds all other threads which were running parallel and returns the handle only after the function GetResult returns.

Please help me to know if this is anything related to the VB6 Activex dll and if there is any known solution for this. I have not written much codes in VB6.

Thanks and Prayers in advance for anyone who helps,
Raaz