I put together a 2+2 14-week mock league into BLS-2014 (my version is 26.06.05) without issue and was able to set position rounds for each week of this league and they were all set to the first two games, with the second two games correctly set to be a regular rotation. But I found there to be no limit to the number of position rounds I could assign, and I tried that with both a complement of 16 and 8 teams.
However, I opted to not make week 1 a position round because what would happen is that, with no wins/losses yet, games 1&2 would be bowled 1-2 3-4 5-6 etc. by virtue of team number only, and that would repeat for games 3&4 the first night.
Are you using an updated version of BLS-2014? Please provide your version number and one of us will be able to respond in more detail as to what specific steps you should be taking. You may also reply with the precise steps you are taking on your own and what dialog messages, etc. you are observing. There may be an easy solution to your issue, but we need more information from you.
Finally, the manual, page 76 et seq. has information on setting up rules and part of what you may need will be found on p. 78. The manual may be read in Acrobat Reader on your PC by finding "Program Manual" under the "Help" menu.
Always check, download, and install the most recent update of your software to ensure that issues may have been corrected.