https://bugs.winehq.org/show_bug.cgi?id=47314
--- Comment #2 from nill14 pavel.sklenak@gmail.com --- it definitely helps. Good work.
Unfortunately, it's not the whole story. As part of the installation process, SourceTree contacts bitbucket server and attempts to allocate port at http://localhost:34106/ possibly somehow using IE10.
There are quite some bug reports, an interesting reading, try `google localhost 34106` for more hits.
One of the bugs, well described: https://community.atlassian.com/t5/Sourcetree-questions/Installation-problem...
Image how it looks like: https://jira.atlassian.com/secure/attachment/340388/Startup-Authentication-i...
Shall we close the issue since the original problem was resolved? Any hints what to try now?