Here's my two cents:
The Irrlicht.dll you are running it with is the one found in the \irrlicht-0.10.0\bin\Win32-VisualStudio (that is, your compiler is either putting the *.exe there, or you are moving it there)
If you are compliing with Dev-C++, you need to put the executable with the Irrlicht.dll found in \irrlicht-0.10.0\bin\Win32-gcc
Give it shot.