You can use the following to get the member's post count:
Dim intMemPostCount
'## Forum_SQL - Get Member's post count
strSql = "SELECT M_NAME, M_USERNAME, M_POSTS "
strSql = strSql & " FROM " & strMemberTablePrefix & "MEMBERS"
strSql = strSql & " WHERE " & strDBNTSQLName&" = '" & strDBNTUserName & "'"
set rsPosts = my_conn.Execute (strSql)
intMemPostCount = rsPosts("M_POSTS")
rsPosts.close
set rsPosts = nothing
Then you could use the following to determine if the link should be shown: (I'm using 100 posts as an example)
if intMemPostCount > 100 then
show link
end if