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Depending on the version of *NIX you are using, there are limitations on the length or number of command line arguments, set in kernel. Some platforms have a limit of 255 entries, Linux has a size limit instead which defaults to (last time I looked) 32 pages (128kb on 32-bit Intel), but this can be changed by tweeking a kernel parameter.
Check the number, and size, of parameters being sent in the command.