HI,
Thank you very much for help , basically i am beginner so it is quite confusing for me, i am pasting the Error again following in order to seek help
Info: Found 2 design units, including 1 entities, in source file latchSR.vhd
Info: Found design unit 1: latchSR-rtl
Info: Found entity 1: latchSR
Error (10430): VHDL Primary Unit Declaration error at modulatore30aprile.vhd(devil): primary unit "modulatore30aprile" already exists in library "work"
Info (10499): VHDL information at azhar.vhd(devil): object "modulatore30aprile" is declared here
Info: Found 0 design units, including 0 entities, in source file modulatore30aprile.vhd
Info: Found 2 design units, including 1 entities, in source file modulatore30apriletest.vhd
Info: Found design unit 1: modulatore30apriletest-architettura1
Info: Found entity 1: modulatore30apriletest
Error (10430): VHDL Primary Unit Declaration error at modulatore_finale.vhd(devil): primary unit "modulatore_finale" already exists in library "work"Info: Found 2 design units, including 1 entities, in source file sel_shift.vhd
Info: Found design unit 1: sel_shift-scalamento
Info: Found entity 1: sel_shift
Info: Found 2 design units, including 0 entities, in source file sine_package.vhd
Info: Found design unit 1: sine_package
Info: Found design unit 2: sine_package-body
Info: Found 2 design units, including 1 entities, in source file sine_wave.vhd
Info: Found design unit 1: sine_wave-arch1
Info: Found entity 1: sine_wave
Info: Found 2 design units, including 1 entities, in source file sinewavecomplex.vhd
Info: Found design unit 1: sinewavecomplex-arch11
Info: Found entity 1: sinewavecomplex
Info: Found 2 design units, including 1 entities, in source file Vhdl2.vhd
Info: Found design unit 1: vhdl2-rtl
Info: Found entity 1: vhdl2
Error: Quartus II Analysis & Synthesis was unsuccessful. 2 errors, 0 warnings
Info: Allocated 151 megabytes of memory during processing
Error: Processing ended: Mon Jul 08 15:31:40 2013
Error: Elapsed time: 00:00:02
Error: Quartus II Full Compilation was unsuccessful. 2 errors, 0 warnings
could you please help?