Dear Sir,
At the outset only, let me tell u the thread that demarcates between Capital and Revenue Expenditures is very thin in some situations........One has to apply his/her own judgement............
Now coming to ur case - There are certain NON MUTUALLY EXCLUSIVE (one may stop u but the other can permit u) indicators (BUT NOT CONCLUSIVE) from which u can decide the nature of this warranty charges -
1) The period covered under warranty - If exceeds 1 year then can be considered as Capital but again it can also be considered as deffered revenue/prepaid expense. Plus even if it is of 1 year stil it can be considered as Capital depending upon the (2) point.
2) Whether the payment made on account of warranty was ESSENTIAL (it includes essential from the prudence angle and not necessarily arising from the contract with the vendor) to bring the asset into acquisition/existence - If yes then it can be considered as Capital Item
3) The fact which u have mentioned that Payment is made at the time of acquisition - It also indicates towards Capital only.
To conclude I feel it is a capital item only..................