After compiling with no errors and after testing the device with the H3DAPI 2.1 examples successfully, i tried to launch H3DLoad.
During initialization, the following sequence happens :

[...]
DeviceInfo *devInfo=new DeviceInfo;
[...]
AutoRef<Group> group(new Group);
H3DHapticsDevice *device=new AnyDevice;
[...]
device->hapticsRenderer->setValue(new GodObjectRenderer);
Group *dg=new Group;
[...]
devInfo->device->push_back(device);
group->children->push_back(devInfo);

And my problem happens on this last line. When calling push_back on children, i get a message saying that the procedure is not found. Since this is a low level procedure, i don't know where to look to understand and correct this bug...
Would anybody have had the same problem ? Any idea what could be the origin for this problem ?
Thank you in advance for any help

So the H3DAPI 2.1 examples that use H3DLoad works fine?

Did you modify H3DLoad in any way?
Is the devInfo variable still valid or did the devInfo get deleted somehow?

Did you make sure that all the loaded dlls are the ones that you compiled (that is, did you build the INSTALL project?)

I compiled again and had the "fish" example working with the standard H3DLoad. I build the INSTALL project before doing that.

The H3DLoad i use is not at all the standard one, it has been rewritten and is used within another project, but it is working fine on other computers.
The devinfo variable seems valid, it has not been deleted.

And you are sure that you do not have any other versions of H3DAPI.dll/HAPI.dll or H3DUtil.dll on your system? Only those,

It really sounds like some dll incompability problem to me.

If some dll was missing then it should complain about that instead, you could try dependency walker just in case.

Standard H3DLoad seems fine, which makes me suspect that you might be building against wrong libraries somehow? Can this be the case?

Thank you a lot for your suggestion Markus, it was exactly that. I have one version of those three files in the /bin directory, and another version in the respective build directories of the three projects (H3DAPI, HAPI and H3DUtil).
I copied the .dll manually, and it made the bug disappear.
What i am wondering now is if there is no other way than copying manually from the build directories into the /bin directory... I might not need it, but it would be a lot cleaner if i could do so.
Thank you again a lot for helping me there.

If you build the INSTALL project of your solution it should copy the files to the correct bin directory. Note that it only copies the files in the solution that you built, so it might be that you forgot to do it for the library files and then switched to an H3DLoad only solution.