Does UBUNTU need any Antivirus ?

[electroguy]

When I try to install Comodo AV it says "The installation of a ................................This could cause serious problems on your computer........................."

Is it safe to install ?

[cortman]

This just means that it's not a well written package/program. It could cause filesystem errors or simply not work.
If you're careful with your passwords, Ubuntu is pretty safe for the average user. I wouldn't say you need anti-virus.
I'll also quote you my favorite piece on anti-virus programs in GNU/Linux, from The Unix Koans of Master Foo:

Master Foo and the Nervous Novice

There was a novice who learned much at the Master's feet, but felt something to be missing. After meditating on his doubts for some time, he found the courage to approach Master Foo about his problem.
"Master Foo,"� he asked "why do Unix users not employ antivirus programs? And defragmentors? And malware cleaners?"�
Master Foo smiled, and said "When your house is well constructed, there is no need to add pillars to keep the roof in place."�
The novice replied "Would it not be better to use these things anyway, just to be certain?"�
Master Foo reached for a nearby ball of string, and began wrapping it around the novice's feet.
"What are you doing?"� the novice asked in surprise.
Master Foo replied simply: "Tying your shoes."�
Upon hearing this, the novice was enlightened.

[Frogs Hair]

If you are sharing files with unprotected Windows machines then yes . Please see the stickies in the security sub forums and the link. https://wiki.ubuntu.com/BasicSecurity

[electroguy]

Thanks for the information! But how to be safe from any infected pen drive that is coming from windows or mac.

[QIII]

Moved to Recurring Discussions

[Frogs Hair]

Thanks for the information! But how to be safe from any infected pen drive that is coming from windows or mac.

Mac and Windows malware/viruses won't run on Linux . Please search this topic there are numerous threads and that is why yours was moved.