[R] knapsack problem limitation

[e-letter]

Readers,

Attempting to solve the knapsack problem (e.g. see:
http://rosettacode.org/wiki/Knapsack_problem/Unbounded), the following
error occurred:

...
result would be too long a vector

Is this indicative that R is not suitable to solve this problem when
combinations are large?
Is there a known limit?
Is there an alternative, or better to use a different program?

Thanks.