I tried test%folder, test%folder% and %folder% and they all worked fine with Favorites.
The first two worked fine when navigating by typing and pasting paths into the path field.
The %folder% example confused things slightly, when typing it into the path field, since it looks like an environment variable and when you press \ and then & Opus clears the start of the path. Pasting the full path into the field works fine, though.
Double-clicking also works fine.
If you are referencing paths with % in them in batch files or command-lines for other programs then you may need to double them up as %% to avoid the programs, or Windows itself, interpreting them as environment variables. (That isn't an Opus-specific thing, though.)
Renaming also works fine for me. Can you give exact details of what you are renaming from and to, and how you're doing the rename? (F2 inline rename? Rename dialog? Simple or advanced rename? Wildcards?)
G:\FTP%ROOT% to G:\FTP=ROOT=,
G:\FTP%%ROOT%% to G:\FTP==ROOT==,
etc.
I tried this by pressing "F2" (inline rename) on the folder name.
On renaming DOpus shows the above mentioned error (number 3) and isn't able to rename.
If I try the same in Explorer, I can rename the folders and DOpus can interact with the renamed folders afterwards.
DOpus was/is setup to replace Explorer on the mentioned system(WINXP_pro sp2).
I've checked with Unlocker if there were any other programs using the folders before/during the rename, but other then DOpus, witch makes perfect sense to me, no other application is using the folders.
When I try to open them from the favorites menu, the same error appears, but I can press the "parent" button in the error display that will open the folder:
G:\FTP
So to put it short:
everything before the %ROOT% folders can be renamed with DOpus, no problem ;
everything after and including the %ROOT% folders can't be renamed with DOpus and gives the number 3 error message.
PS: the contents of the %ROOT% folders are .bf2demo files (BF2 Battlerecorder generated movies)
Don't know for sure if you needed to know this, just mentioned it to be thorough..