See KB Article KB168958 "HOWTO: Exporting STL Components Inside &
Outside of a Class". Pay attention to the part where it says
In both the DLL and the .exe file, link with the same DLL version of the
C run time. Either link both with Msvcrt.lib (release build) or link
both with Msvcrtd.lib (debug build).
There's no chance of it working properly otherwise.
With best wishes,
"For every complex problem, there is a solution that is simple, neat,
and wrong." H.L. Mencken