We retested with Twonky on a NAS drive here and it works.
Try a small test library.
I have 4 directories, Blues is the smallest
Configured Twonky to scan directory Blues
This works, MC15 reports 1114 files, a mixture of WMAL and MP3
Added the Jazz directory, again a mixture of WMAL and MP3, no other file types.
Together they total to 3378 files. Works
Added the Classical directory, connected when the server reported 5000 files.
Now I get the load error