Accepting personal responsibly for ones actions is one of the fundamental precepts of Judaism. "Man is always liable" for damages caused, the Talmud declares even if such damages were caused while sleeping. This concept applies equally to damages caused by our possessions. Thus owners of animals are liable for damages inflicted by their pets, the details of which take up much Talmudic discussion. What was true regarding animals in Talmudic times is equally true today regarding cars, computers or corporate assets. You are responsible for ensuring your emails are virus free. Conversely a parent can not be held liable for damages caused by their minor child; a child is not owned by the parent.
Jewish law therefore does not accept the notion that workers negligence should be borne by the employer. In a well known Talmudic passage a group of needy workers who broke a valuable barrel of wine were to pay out of pocket the total amount of the damages less any wages they were otherwise entitled to. Only the Talmudic sage Rav's insistence that the employer, a rabbinic scholar himself, act beyond the letter of the law, freed the indigent workers of their liability and also allowed them to collect their salaries. But such demands are not necessarily placed on an 'average' employer nor given to workers who are not classified as poor. Thus a worker who carelessly erases important computer files or whose rude demeanor chases away clients is to be held responsible for looses incurred.
Yet while we must ensure that people take their responsibilities seriously Jewish law is cognizant of the fact that being excessively harsh on those who commit errors will scare away people from taking on more difficult tasks. It benefits nobody if fear of making a mistake rules the workplace. Thus as a practical measure a worker who causes a financial loss is to take an oath that they were not negligent thereby exempting themselves from payment. This rabbinic willingness to enact -and even change - laws to promote business growth is a common feature of Jewish civil law. Whereas, for example, Torah law requires a creditor to produce two witnesses (who must then be cross examined) in order to collect monies owing, the Talmudic Sages relaxed the standards of evidence required in order to ensure that creditors would continue to loan money.