CVI ships with multiple example DLL projects that can help you understand how to create and call DLLs in CVI. In your case, as Anna said, you need to call functions in a DLL, not create a DLL in CVI. You need to use your Fortran compiler to create the DLL and .LIB file, and then you can use CVI to call functions in that DLL.
Look at the simple DLL example projects in C:\Documents and Settings\All Users\Documents\National Instruments\CVI90\samples\dll\simple\cvi. (Note: the directory may be different depending on your CVI installation and version.)
First you need to build the DLL. Open mydll.prj, then, from the CVI menu, select Build >> Create Debuggable Dynamic Link Library. This is the step in your real project that you will need to do using your Fortran compiler.
Then build the executable to call functions from your DLL. Open simple.prj, then Build >> Create Debuggable Executable. You can now run your project, and browse simple.c to see how it calls functions in your DLL.
Remember that for the purpose of this example, you're building a DLL in CVI, but for your real project, you'll be using your Fortran compiler to build your DLL and LIB. Copy the DLL and LIB files to your CVI project directory, add the LIB file to your CVI project, and in your .c file which will call the DLL functions, #include a .h file which contains the prototypes for the DLL functions you'll be calling.
