Some questions about some sentances from a childrens story.

干活,干do,活work, often refers to physical labour
do some work:干一些活,some work needs to be done,有一些活需要干.
影子: literally it means shadow, but 'no shadow of wolf' is to say that no trace of any wolf appearing. No sign of sth.
被is about passive voice, it's like the 'be done by' in English. '
咬bite, the child was bitten by the wolf, 伤injure
so被咬伤 is ‘get injured from being bitten’
Children were bitten by the wolf and they got injured.

叼 is the action of holding sth in the mouth and leave most parts of the object outside of the mouth. This action is often done by animals. But you may say a man 叼 a cigarette, because most parts of the cigarette is not contained in his mouth. However, such expression implies the man with the cigarette is wild. e.g. The hooligan/village people叼a cigarette.
No offence to them, just give these examples to help you understand the verb better.
The wolf carried the lamb away in its mouth.

害得means ‘(bad thing or person) makes....’, often leading to a very serious, catastrophic situation, it's an informal expression.
e.g.电梯坏了,害得我爬了十五层楼梯.
In your case, it means the situation is very bad, it made the farmers.....
白跑means: go to somewhere (for doing sth), but in vain. e.g.办事处今天休息，害得我白跑了一趟.
好几趟: several times
eg.办事处最近一直休息，害得我白跑了好几趟.
So the last sentence in English would be: It made the farmers do serveral vain attempts.
I'm no translation expert but I think it's really hard to translate the last sentence word by word, it would come out a very odd Chinese-English sentence, instead of a real English sentence. I suppose the English sentence I made up is not so good either. Anyway, you understand these words now, right? I think this is exactly what we're looking for, not the translation itself.