It is almost certain that you cannot use it directly from B4PPC but if you have the required knowledge (or know someone who does) then it is probably (but not definitely) possible to write a C# or VB .NET dll in #develop or Visual Studio that B4PPC can use as an intermediary between the scanner dll and B4PPC.
As agraham described, if you are not familiar it could be difficult to use this DLL.
I think that PRETEC CF scanner has a keyboard emulator (scanning is like someone types the barcode characters through keyboard). Better use this than the DLL (if it really exists).