Perguntas Campo MEMO

Criei um campo do tipo MEMO na tabela CNB, e não coloquei nenhuma validação.
Mas se eu não colocar algum coisa nele ocorre um erro log e aborta o sistema.

abaixo o erro:

ERRO THREAD (harley.dias, NB456) 06/02/2012 14:13:04
expected string expression in FieldPut CNB_YDESC in file .\dbenv.cpp at line 622
on CN140GERPLAN(CNTA140.PRW) 20/07/2011 19:28:03 line : 3944

[TOTVS build: 7.00.101202A-20110919]
Called from CN140GERREV(CNTA140.PRW) 20/07/2011 19:28:03 line : 3010
Called from {||CN140GERREV(CCONTRA,CREVISA,CCODTR,CJUST,CCODPR,DDTREIN,DDTREAJ,CCLAUS,AITENS,APLAN,@APARCELAS,ACRON,DFCONTRA,AHEADERIT,AHEADPARC,ACOLSPARC,AITENSCTB,NVALOR,LALTVLR,NVGADIT)}(CNTA140.PRW) 20/07/2011 19:28:03 line : 686
Called from eval line : 143
Called from {|| IF(EVAL(SELF:ABVALID[SELF:NPANEL,3]),SELF:NAVIGATOR(0),)}(APWIZARD.PRW) 29/09/2008 13:48:07 line : 143
Called from ::MSDIALOG:ACTIVATE
Called from APWIZARD:ACTIVATE(APWIZARD.PRW) 29/09/2008 13:48:07 line : 159
Called from CN140MANUT(CNTA140.PRW) 20/07/2011 19:28:03 line : 709
Called from EXECBROW(MSLIB.PRW) 14/09/2011 18:00:39 line : 982
Called from {|aArray,nPos,aSvRotina,lRunPopUp| aSvRotina := Aclone(aRotina), If(aArray <> NIL,aRotina := Aclone(aArray),),SetEnch(aRotina[nPos][1]), inclui := (aRotina[nPos][4] == 3), altera := (aRotina[nPos][4] == 4), ExecBrow(aRotina[nPos][2],If(Len(aRotina[nPos]) > 4,aRotina[nPos][5],),nPos,'CN9',@aEncho,,'xFilial("CN9")','xFilial("CN9")', .F.,.T.,lSeeAll .and. lBrwFilOn,.T.,.T.,lRunPopUp),If(lAxPesqui,MbrSetAllCols(cAlias,aIdxCol),),aRotina := Aclone(aSvRotina)} line : 8159
Called from eval line : 8186
Called from {|| Eval(bExecBrow,, 3)} line : 8186
Called from ::TDIALOG:ACTIVATE
Called from MBRWINDOW(MSLIB.PRW) 14/09/2011 18:00:39 line : 8409
Called from MBROWSE(MSLIB.PRW) 14/09/2011 18:00:39 line : 622
Called from CNTA140(CNTA140.PRW) 20/07/2011 19:28:03 line : 113
Called from __EXECUTE(APLIB090.PRW) 27/09/2011 13:30:31 line : 1100
Called from {|| Iif(!__GetClicked(),(__SetClicked(.T.), Eval(oApp:oSplitClose:bLClicked), __Execute('CNTA140()','xxxxxxxxxx','Revisoes','69','Revisoes',1), Eval(oApp:oSplitOpen:bLClicked), __SetClicked(.F.)),)} line : 177
Called from ::TWINDOW:ACTIVATE
Called from MSAPP:SKINP10APP(APLIB000.PRW) 18/10/2011 11:37:17 line : 1566
Called from MSAPP:RUNAPP(APLIB000.PRW) 18/10/2011 11:37:17 line : 801
Called from SIGAADV(APLIB000.PRW) 18/10/2011 11:37:17 line : 2565

Estou tendo o mesmo problema, como que foi resolvido esse problema?

Tentei a opção do Sr. Luiz Alberto e ainda não resolveu.