Failed to set default directory / file specification syntax error

We work with a company who requires that data files be transferred via FTP, and we have historically used to Filezilla to accomplish this. We're wanting to transition to using WinSCP in order to automate the upload process, but when I attempt connect to our partner's FTP site (using the same credentials that were used to successully connect with Filezilla), I receive the an error saying:

"Could not retrieve directory listing
Failed to set default directory to /DKC2:[CLIENTS.TQL]
file specification syntax error"

It appears that I'm able to connect to their FTP site, yet am unable to connect to the correct remote directory. Again, I'm using the same credentials that I've been using to upload files through Filezilla. Does this look like an issue with the way the client is configured? Any help would be greatly appreciated.

Thanks!

Please attach a full session log file showing the problem (using the latest version of WinSCP).

Though note that WinSCP does not support well servers, that do not follow common *nix path format (like IBM VMS, MVS, etc).