Include the .DLL in your project so it gets compiled inside the .EXE, and when your app starts up, generate a random name with Sys(3) and copy it to your temp directory and use it from there. That's what I do with FLL's (I don't use any DLLs that are not COM objects and all COM objects get registered at install time).

Something like

* cTempDir is defined earlier in the program
  Declare Sleep IN WIN32API Integer
  cFoxToolsName = cTempDir +  "FT" + Sys(3) + ".FLL"
  nNothing = Sleep(1000)
  Copy File FoxTools.FLL to ( cFoxToolsName )
  Set Library to (cFoxToolsName)  Additive

I think another advantage to doing it this way is that if your stuff is a COM object itself and might be instanced multiple times each instance can have its own copy and instances won't step on each other.