CFD Online Discussion Forums - [Other] Need some help here

can somebody pls point out the error/errors here..this is my first go at openFOAM and im getting this error
"No non-linear edges defined
Creating topology blocks

--> FOAM FATAL IO ERROR:
Attempt to return dictionary entry as a primitive

file: /home/prashanth/OpenFOAM/prashanth-2.0.1/run/firsttry/constant/polyMesh/blockMeshDict::blocks from line 24 to line 35.

From function ITstream& primitiveEntry::stream() const
in file db/dictionary/dictionaryEntry/dictionaryEntry.C at line 82.

FOAM aborting

#0 Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam201/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#1 Foam::IOerror::abort() in "/opt/openfoam201/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#2 Foam::dictionaryEntry::stream() const in "/opt/openfoam201/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#3 Foam::dictionary::lookup(Foam::word const&, bool, bool) const in "/opt/openfoam201/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#4 Foam::blockMesh::createTopology(Foam::IOdictionary const&, Foam::word const&) in "/opt/openfoam201/platforms/linuxGccDPOpt/lib/libblockMesh.so"
#5 Foam::blockMesh::blockMesh(Foam::IOdictionary const&, Foam::word const&) in "/opt/openfoam201/platforms/linuxGccDPOpt/lib/libblockMesh.so"
#6
in "/opt/openfoam201/platforms/linuxGccDPOpt/bin/blockMesh"
#7 __libc_start_main in "/lib/i386-linux-gnu/libc.so.6"
#8
in "/opt/openfoam201/platforms/linuxGccDPOpt/bin/blockMesh"
Aborted"

FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}

convertToMeters 0.01;

vertices
(
(0 0 0)
(0 5 0)
(5 5 0)
(5 0 0)
(0 5 -10)
(0 5 -10)
(5 5 -10)
(5 0 -10)
);

blocks
{hex (0 1 2 3 4 5 6 7) (20 20 1) simpleGrading(1 1 1)};
edges
(
);

boundary
( inlet
{type patch;
faces
(
(3 2 1 0);
);
}

outlet
{type patch;
faces
(
(4 5 6 7);
);}

walls
{type wall
faces
(
(6 5 2 1)
(3 0 4 7)
);}
frontandback
{type empty
faces
(
(2 3 7 6)
(4 5 0 1)
);
}
mergePatchPairs
();