With UTF-8 encoding becoming the default, I've been noticing strange characters appearing when connected to newer linux distros via SecureCRT. Turns out this is due to a combination of settings. This site details a solution.
http://www.andremiller.net/content/getting-midnight-commander-line-drawing-work-putty
Basically, change the character set translation to UTF-8 and the line drawing to UTF-8 and the font to one that supports UTF-8 line characters (Lucida Console, Courier new work - others may as well).
Here's a link for improvements to putty/SecureCRT:
http://dag.wieers.com/blog/improving-putty-settings-on-windows