dosfsck unable to truncate files

I found dosfsck (dosfsck 2.11, 12 Mar 2005) unable to truncate file when two files
share the same cluster and you want to truncate the 1st file. (the program exits
with :
"Internal error: didn't find cluster xxxx in chain starting at 0")

i had a look at the code, and i found that this message (in check.c:510) will
nearly always happen
because of the condition.
i add the following line:
--- 501,505 ----
                            this = next_cluster(fs,this);
                        }
+ this=curr;
                        break;
                    }

then it seems to work (i repaired my partition with the patched version)

best wishes