Help Needed Regarding Parsing error

I am working on NVIDAI GForce GT9800 and i suddenly got this error and unable to debug it.
"Error 93 Parsing error near ‘.address_size’: syntax error ptxas C:/Users/apibs/AppData/Local/Temp/tmpxft_00000f94_00000000-4_program1.compute_20.ptx, line 3; fatal program1

i also reinstall the toolkit and Visual studio but nothing works all cpp files works fine but this problem occurs with cu files only.