If that doesn't work, then we have hit the same brick wall I hit when trying to install Steam, which forced me to copy my Steam install off of my Windows partition (hence why I asked you about a Windows install). Supposedly one or both of the things I have told you to do will correct the 26% update problem, but they never worked for me. Maybe one of the other Steam users on the forum can help with it, but if this last one doesn't fix it, I'm out of ideas.
cd .wine/drive_c/Program\ Files/Steam
wine SteamTmp.exe SelfUpdate "C:\Program Files\Steam\Steam.exe" 14