Debug a Cryptography class

I have a Cryptography class called clsDES that was written a few years ago.? The class encrypts and decrypts data based on a 3 part string and a key.? It works ... 95% of the time.? But I currently have a string that it will not encrypt (I suspect it is too long). I use the stored encryption of the 3 part string to control software subscription expire dates. I want an EXPERIENCED programmer to debug and fix the problem.? But the solution must, repeat MUST, still decrypt the old codes. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows? (depending on the nature? of the deliverables): a)? For web sites or? other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software? installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform The attached file contains the class that needs to be fixed. The project must remain in Visual Basic.