I assume your problem is the client.dll error. If so, you should read the stickies in this section or located in other sections.
Basically this happens because ESF is running on an older version of the fmod.dll. This will be fixed in the 1.2.1 patch. But for now, I believe that esf-world.de has the fmod.dll for download from their site.
I would search around for the appropriate sticky, and there may even be a thread or two discussing this very issue. But in the future, instead of typing in all caps and giving us no useful information whatsoever, perhaps it would be better to give us as many details about the problem so we can accurately and hastily assess and hopefully help you resolve your problem.
Thanks in advance