This is not a bug but a simple bash feature! Let's explain with an example:
---[
# echo 123&456
[1] 5489
123
-bash: 456: command not found
[1]+ Done echo 123
#
]---
This happens because the ampersand '&' is a character used to run in background a process!
So if you need to use it in an URL you must double-quote it:
./openwebspider -s -i...