The problem stems from a missing DLL, if you have had this problem.

// Tech Note: On some Windows 95 PCs when you issue the command:
//
// SET LIBRARY TO cipher50.fll
//
// you may experience an error similar to:
//
// Error 1691 - Library file Cipher50.FLL is invalid.
//
// The error is a result of the Windows PC not having MSVCRT.DLL installed
// in its SYSTEM directory. The problem does not occur with Windows NT.
// Microsoft states that MSVCRT.DLL is required with multithreaded .DLLs
// [or .FLLs] by design. However, it is not shipped with all O/S products.
//
// Microsoft ships this .DLL with Windows NT 4.0, OEM Service Release 2 of
// Windows 95 (OSR 2), and MS VC++ 4.2 and higher. It does NOT ship with
// the original version of Windows 95, the Windows 95 Upgrade, the Win95
// Service Pack 1, or VFP 5.0.
//
// MSVCRT.DLL [version 5.0.7022] is now included with CIPHER50.ZIP. If you
// distribute CIPHER50 enabled applications with the VFP 5.0 Setup Wizard,
// remember to direct MSVCRT.DLL to WinSysDir in step 6 of the Setup Wizard.
//
// Occassionally, there may be difficulty installing a .DLL in the SYSTEM
// directory due to the .DLL being in use at the time of a new install.
// However, installing this particular .DLL should be fairly painless since
// it is not one of the active .DLLs that is always [or often] running. The
// fact that it is not part of the original version of Windows testifies to
// this.
//
// As another work around for a Windows 95 PC that does not have MSVCRT.DLL,
// copying MSVCRT40.DLL to MSVCRT.DLL in the SYSTEM directory has been known
// to work.
//
// Refer to the MS Knowledge Base Article Q157317 for additional information
// regarding .FLLs and MSVCRT.DLL.

I will upload the more complete ZIP file shortly.