R code debugging

Dear useRs,

it's quite difficult for me to find `Error:'s in my R code, because R does
say about error itself, but say nothing about its location, say, string
number and file with an error (which may be `source'd from another file).
Are there any option for turning of the similar feature, or R can not do
such a thing at all?

Thanks.


--
WBR,
Timur.