FM Error

[cognos05]

Code used in the expression : to get the package name.

if(Position('package[@name=',[Physical Layer].[COGIPF_RUNREPORT].[COGIPF_PACKAGE])>0)
Then
(SubString([Physical Layer].[COGIPF_RUNREPORT].[COGIPF_PACKAGE],position('package[@name=',[Physical Layer].[COGIPF_RUNREPORT].[COGIPF_PACKAGE])+15,(position(']/model',[Physical Layer].[COGIPF_RUNREPORT].[COGIPF_PACKAGE])-1)-
(position('package[@name=',[Physical Layer].[COGIPF_RUNREPORT].[COGIPF_PACKAGE])+15)))
Else
( [Physical Layer].[COGIPF_RUNREPORT].[COGIPF_PACKAGE])

Executes in expression window.but verify model gives error .

Error :
BMT-MD-2001 The property 'Object Reference in Expression' has the value '[@name=',[Physical Layer].[COGIPF_RUNREPORT].[COGIPF_PACKAGE]', which does not reference an existing object. This property must reference an existing object.
BMT-MD-3514 The repair action will prompt to retarget or delete the broken reference.


so '@name ' is it making a issue, what should i do to fix this.