How to resolve "Sevenzip: Error result (00000001) Incorrect function" using JCLcompression unit

Question

I'm using JCL version 2.4.1.4571 with Delphi XE3 and have had no luck decompressing archives. I've downloaded the dll's from JEDI's site and also tried using the 7z.dll (32bit) from 7-zip.org but either way I get the same error when I try to "ExtractAll"

See function below:

function TForm1.Decompress(FileName, DestDir: String): Boolean;

var
  archiveclass: TJclDecompressArchiveClass;
  Myarchive: TJclDecompressArchive;

begin
  Decompress := False;
  // Filename = name.7z or name.zip (simple test zips nothing fancy)
  // DestDir = fully qualified path to an existing directory
  archiveclass := GetArchiveFormats.FindDecompressFormat(FileName); 
  Try
    if Assigned(archiveclass) then
      Begin
        Myarchive := archiveclass.Create(FileName);
        if (Myarchive is TJclSevenZipDecompressArchive) then
          Begin
            try
              Myarchive.ListFiles; { Fails without doing this first }
{ ExtractAll (AutocreateSubDir) must be set true if arc has directories or it will crash }
              Myarchive.ExtractAll(DestDir, True); 
              Decompress := True;
            except on E: EJclCompressionError do
              Begin
                ShowMessage(e.Message); 
              End;
            end;
          End
        Else
          ShowMessage('Not supported by 7z.dll'); 
      End;
  Finally
    MyArchive.Free;
  End;
end;

When I execute the MyArchive.ExtractAll line, I get an exception Sevenzip: Error result (00000001) Incorrect function. I based my code on code from others here on StackOverflow. Am I missing something I need to do first or is this a bug? I've replaced the extract line with MyArchive.ListFiles and get the same error (I saw that in an example here; however, I've yet to divine the purpose of ListFiles.
Compiling to 32bit target.

Edit: Created a series of different types of archives using 7-zip and tried to decompress each with my program. The first thing I discovered is that if the archive contains directories of files, ExtractAll will crash if you don't set the second parameter to True. I then tested archives with different compression methods.

.7z archive using LZMA2 Ultra compression gives the Hresult = 1 error

.zip archive using LZMA Ultra compression gives the Hresult = 1 error

.zip archives using flavors of Deflate or deflate64 all work fine.

It appears that the library doesn't handle LZMA compression at all. Since it makes no sense that the 7z.dll can't handle it, I'm guessing the problem is with the JEDI JCL code. I need to be able to compress/decompress .7z and .zip's using LZMA with this library or I could have just used the built in zip stuff to begin with. Any further suggestions would be appreciated.

Answer 1

Further Googling on this problem turned up http://sourceforge.net/p/jcl/mailman/message/21371812/

It appears "FindDecompressFormat doesn't find archive format if file name is not in lower case."

I tried changing the string I was passing to lowercase and I successfully decompressed an LZMA archive.

archiveclass := GetArchiveFormats.FindDecompressFormat(lowercase(FileName));

JEDI JCL would be a cool library if it had any documentation whatsoever - sad.