Index: example/main.tcl
==================================================================
--- example/main.tcl
+++ example/main.tcl
@@ -71,15 +71,23 @@
 } -cleanup {
 	close $fd
 	unset fd
 } -result ""
 
-tcltest::test xvfs-basic-open-write "Xvfs Open For Writing Test" -setup {
+tcltest::test xvfs-basic-open-neg "Xvfs Open Non-Existant File Test" -body {
+	unset -nocomplain fd
+	set fd [open $rootDir/does-not-exist]
+} -cleanup {
+	if {[info exists fd]} {
+		close $fd
+		unset fd
+	}
+} -returnCodes error -result "no such file or directory"
+
+tcltest::test xvfs-basic-open-write "Xvfs Open For Writing Test" -body {
 	unset -nocomplain fd
-} -body {
 	set fd [open $rootDir/new-file w]
-	close $fd
 } -cleanup {
 	if {[info exists fd]} {
 		close $fd
 		unset fd
 	}
@@ -86,10 +94,21 @@
 	catch {
 		file delete $rootDir/new-file
 	}
 } -match glob -returnCodes error -result "*read*only file*system*"
 
+tcltest::test xvfs-basic-open-directory "Xvfs Open Directory Test" -body {
+	unset -nocomplain fd
+	set fd [open $rootDir/lib]
+	set fd
+} -cleanup {
+	if {[info exists fd]} {
+		close $fd
+		unset fd
+	}
+} -match glob -returnCodes error -result "*illegal operation on a directory"
+
 tcltest::test xvfs-basic-two-files "Xvfs Multiple Open Files Test" -setup {
 	set fd1 [open $testFile]
 	set fd2 [open $testFile]
 } -body {
 	set data1 [read $fd1]
@@ -188,10 +207,16 @@
 	file stat $testFile fileInfo
 	set fileInfo(type)
 } -cleanup {
 	unset -nocomplain fileInfo
 } -result file
+
+tcltest::test xvfs-stat-basic-file-neg "Xvfs stat Basic File Negative Test" -body {
+	file stat $rootDir/does-not-exist fileInfo
+} -cleanup {
+	unset -nocomplain fileInfo
+} -match glob -returnCodes error -result "*no such file or directory"
 
 tcltest::test xvfs-stat-basic-dir "Xvfs stat Basic Directory Test" -body {
 	file stat $rootDir/lib fileInfo
 	set fileInfo(type)
 } -cleanup {

Index: xvfs-core.c
==================================================================
--- xvfs-core.c
+++ xvfs-core.c
@@ -169,10 +169,21 @@
 			return("Internal error");
 		default:
 			return("Unknown error");
 	}
 }
+
+static void xvfs_setresults_error(Tcl_Interp *interp, int xvfs_error) {
+	if (!interp) {
+		return;
+	}
+
+	Tcl_SetErrno(xvfs_errorToErrno(xvfs_error));
+	Tcl_SetResult(interp, (char *) xvfs_perror(xvfs_error), NULL);
+
+	return;
+}
 
 /*
  * Xvfs Memory Channel
  */
 struct xvfs_tclfs_channel_id {
@@ -189,11 +200,11 @@
 	Tcl_Event tcl;
 	struct xvfs_tclfs_channel_id *channelInstanceData;
 };
 static Tcl_ChannelType xvfs_tclfs_channelType;
 
-static Tcl_Channel xvfs_tclfs_openChannel(Tcl_Obj *path, struct xvfs_tclfs_instance_info *instanceInfo) {
+static Tcl_Channel xvfs_tclfs_openChannel(Tcl_Interp *interp, Tcl_Obj *path, struct xvfs_tclfs_instance_info *instanceInfo) {
 	struct xvfs_tclfs_channel_id *channelInstanceData;
 	Tcl_Channel channel;
 	Tcl_StatBuf fileInfo;
 	Tcl_Obj *channelName;
 	int statRet;
@@ -202,10 +213,21 @@
 	XVFS_DEBUG_PRINTF("Opening file \"%s\" ...", Tcl_GetString(path));
 
 	statRet = instanceInfo->fsInfo->getStatProc(Tcl_GetString(path), &fileInfo);
 	if (statRet < 0) {
 		XVFS_DEBUG_PRINTF("... failed: %s", xvfs_perror(statRet));
+
+		xvfs_setresults_error(interp, XVFS_RV_ERR_ENOENT);
+
+		XVFS_DEBUG_LEAVE;
+		return(NULL);
+	}
+
+	if (fileInfo.st_mode & 040000) {
+		XVFS_DEBUG_PUTS("... failed (cannot open directories)");
+
+		xvfs_setresults_error(interp, XVFS_RV_ERR_EISDIR);
 
 		XVFS_DEBUG_LEAVE;
 		return(NULL);
 	}
 
@@ -575,14 +597,11 @@
 	XVFS_DEBUG_PRINTF("Asked to open(\"%s\", %x)...", Tcl_GetString(path), mode);
 
 	if (mode & O_WRONLY) {
 		XVFS_DEBUG_PUTS("... failed (asked to open for writing)");
 
-		if (interp) {
-			Tcl_SetErrno(xvfs_errorToErrno(XVFS_RV_ERR_EROFS));
-			Tcl_SetResult(interp, (char *) Tcl_PosixError(interp), NULL);
-		}
+		xvfs_setresults_error(interp, XVFS_RV_ERR_EROFS);
 
 		XVFS_DEBUG_LEAVE;
 		return(NULL);
 	}
 
@@ -594,11 +613,11 @@
 
 	Tcl_DecrRefCount(path);
 
 	XVFS_DEBUG_PUTS("... done, passing off to channel handler");
 
-	retval = xvfs_tclfs_openChannel(pathRel, instanceInfo);
+	retval = xvfs_tclfs_openChannel(interp, pathRel, instanceInfo);
 
 	XVFS_DEBUG_LEAVE;
 	return(retval);
 }
 
@@ -732,13 +751,11 @@
 	if (!pathStr) {
 		XVFS_DEBUG_PUTS("... error (not in our VFS)");
 
 		Tcl_DecrRefCount(path);
 
-		if (interp) {
-			Tcl_SetResult(interp, (char *) xvfs_perror(XVFS_RV_ERR_ENOENT), NULL);
-		}
+		xvfs_setresults_error(interp, XVFS_RV_ERR_ENOENT);
 
 		XVFS_DEBUG_LEAVE;
 		return(TCL_OK);
 	}
 
@@ -747,13 +764,11 @@
 	if (childrenCount < 0) {
 		XVFS_DEBUG_PRINTF("... error: %s", xvfs_perror(childrenCount));
 
 		Tcl_DecrRefCount(path);
 
-		if (interp) {
-			Tcl_SetResult(interp, (char *) xvfs_perror(childrenCount), NULL);
-		}
+		xvfs_setresults_error(interp, childrenCount);
 
 		XVFS_DEBUG_LEAVE;
 		return(TCL_ERROR);
 	}