Hi,
It seems that you have missed out some dlls in your project.
Please follow these steps to solve your problem.
1. I hope you installed the devexpress in your system. let assume the poth as "c:\devExpress\"
2. Open you project or solution in Visual Studio and right click on the solution, just select "Add Reference" in the floating menu.
3. Select the dll available in the above devExpress location. Those dlls are just moved in to the "bin" folder of your solution.
4. Now compile the application.
In Some situations, you may have the reference the above dll in your application.
You should check that, the application pool you are using is compatible with the assembly.
I have encountered these kind of errors in my past. Please check that dll is 32 or 64 bit.
If it is 32 bit, then open the IIS and select the respective app pool and go to "Advanced setting" and "Enable 32-bit Applications" to "True".
Hopes this helps!
Thanks!
S Francis
My ASPDotNet Blog