Bex-error reading from infoprovider

Hi,

I am loading from ods1 to ods2.

ods1:

Key fields-Customer Number

Data fields-Date1 and Date2

ods2:

Key fields-Customer Number

Data fields-Date1,Date2,P1,P2,P3.

In transformation i written field level routine to P1,P2 and P3..

If Date1 is having data then P1 is filled with ' X'

P2 is based on Date2

P3 is based on both Date1 and Date2

Data got loaded into ODS2 and request also successfully activated.

When query is created on ODS2 and while executing i am getting following error

Error reading the data of InfoProvider

ORA-01722: invalid number

What is reason for above error and how to rectify this error..Suggest ur ideas to get the result

Regards

Prakash