DNG not opening in lightroom

Hi all,

looking for some help.

I use photoshop CS5 and lightroom 2 on a IMAC G5 20inch (2006 model) OSx 10.7.5

DNG files are opening fine in photoshop but in lightroom it is saying

"The file appears to be unsupported or damaged"

DNG version is 8.4.0.199

how can i fix this?

i dont want to upgrade photoshop or lightroom as it good for what i need.

appreciate some help