--- src/cmd/ksh93/sh/lex.c
+++ src/cmd/ksh93/sh/lex.c	2012-01-16 16:09:37.624771155 +0100
@@ -1563,8 +1563,10 @@ static int comsub(register Lex_t *lp, in
 		if(endtok==LPAREN && lp->lexd.paren)
 		{
 
-			if(first==lp->lexd.first)
-				fcseek(cp+1-(char*)fcseek(0));
+			if(first==lp->lexd.first) {
+				const char *tp = (const char*)fcseek(0);
+				fcseek(cp+1-tp);
+			}
 			count++;
 			lp->lexd.paren = 0;
 			fcgetc(c);
@@ -1872,6 +1874,8 @@ static int here_copy(Lex_t *lp,register
 					sfputc(sp,'\\');
 				}
 			}
+			if (LEN < 1)
+				LEN = 1;
 			bufp = fcseek(-LEN);
 		}
 		else