Amit, it would depend to some extent on your contract of employment. I presume it's a fixed term contract and not a permanent position? Is there a trial period, for example does your contract specify that they can fire you after 3 months if they're not happy with you etc. Try asking on a forum for Polish programmers/IT workers. Many of them speak English so you should get some response to your query. They will have a realistic answer for you as they work in the industry.
Hi Amit. Yes, your three month probationary period means that they can let you go after that time if they're not happy with you. But that's a pretty standard clause in many employment contracts worldwide, not just Poland. However I would say that in general Polish employers don't have the best reputation for how they treat staff, but of course it varies.
There's a forum called 4programmers.net. It's a Polish site. Register with them. Go to the section marked Praca (that's Polish for work) and start a thread same as you did here. The site is all in Polish I think but a lot of these guys know English so I'm sure you'll get some response. Also there is a Poland Forum member called Monitor who seems to be very knowledgeable about the IT business so you could send him a PM.