Here is the instruciton borrowed from a Chinese forum
Follow the following steps:
1. save and unzip the file 'pdflrf.zip' to a folder such as "c:\pdflrf".
2. save a copy of the pdf file you want to convert to that folder. For example a file namded 'bullshit.pdf'.
3. click start-> run... and type in 'cmd'. You are in DOS mode
4. Type in 'cd c:\pdflrf'
5. Type in 'pdflrf -i bullshit.pdf -o stillbullshit.lrf -p -v -s'
6. you should have a file stillbullshit.lrf in that folder.
7. try other options and have fun...