400 BAD REQUEST - % symbol is not encoded properly

Hello.

I have a file in the repository that has a % (percent sign) in its path. When I try to view log for it, I get an error like this: "Server sent unexpected return value (400 Bad Request) in response to OPTIONS request for 'http://server:88/svn/sandbox/trunk/%test/test.txt'.
It seems, % in the URL does not get encoded properly.

I was able to trace the error with Fiddler, here is the request causing problems:
OPTIONS http://server2008:88/svn/sandbox/trunk/%25test/test.txt
200 OK

Earlier in the seesion there're requests with properly encoded URLs:

OPTIONS http://server2008:88/svn/sandbox/trunk/%25test/test.txt
200 OK

PROPFIND http://server2008:88/svn/sandbox/trunk/%25test/test.txt
207 Multi-Status
 
I've attached the compelete log from Fiddler: all requests and responses after clicking "Log" in TortoiseSVN.

My configuration:
- TortoiseSVN 1.6.5, Build 16974 - 32 Bit
- SVN Server 1.6.5.38866 + Apache 2.2.13 (VisualSVN Server 2.0.7).