Problem: failed to create task or type antlib:com.salesforce:deploy

Hi, Today while trying to deploy my org's metadata on production using Salesforce's migration tool I faced the error "Problem: failed to create task or type antlib:com.salesforce:deploy".

I was using Ubuntu 11.04 (It should be useful in MAC systems as well), so i discovered the solution to this problem is we need to download the salesforce migration tool from our deployment org's Your Name | Setup | Develop | Tools.

After downloading the zip file on your drive, extract the content and copy the ant-salesforce.jar to /usr/share/ant/lib/ 

This should resolve the particular error.