Redmine

I have installed the subversion link from
http://www.redmine.org/plugins/add_subversion_links

I am able to open the repository link(The subversion icon at the name column).
However when I click the the subversion icon at the revision column, the following errors appear
at TortoiseSVN

can't open svn://host/parent/.svn/entries.
The filename, directory name or volume lable syntax is incorrect.

Please advise what is wrong.
My redmine installation version is v2.0.3 and I have use the latest plugin in
http://www.redmine.org/plugins/add_subversion_links

My tortoisesvn version is TortoiseSVN 1.6.8, Build 19260