Unable to install 5.0 on rooted N5 topic

Hi guys ,

I have a rooted nexus 5 running on original stock rom with clockwork recovery installed. I have been getting pop ups to download Andriod 5.0 for last 10 days , Every time I download it , it takes me to recovery and than gives me a message "unable to open the package etc." and cancels the install.

I have tried clearing up the cache , did factory reset , same result everytime.
Any suggestions what can i do ?