in version 10.0.3.6288 when calling $core_v2_forumReply.GetForumReplyPageIndex or forumReplies.GetPageIndex when the parameter IncludeThreadStarter is set to true, the result returned is always zero. I think this is a bug.
First, you will need to share how you are using it, as in the code you are trying to get to work.Second, I recommend looking at upgrading to at least the latest version of 10.1. At this time normal maintenance is not being done on 10.0
So without seeing your data, are you sure that is not correct? That the reply in question is not index 0? What is it you are trying to accomplish?
And I mean on page index 0
when i remove the parameter IncludeThreadStarter, the page index is returned correctly, when i set it to true, the page index is returned as 0.