Alpha conversion error with 0_soldto

Hi,

uploading a z table where one of the fields is the customer number (10 chars), I get the error:

SOLD_TO infoobject contents the value 1 not alpha .

The values in the Z table ten characters long seems not to have problems.

The map is between the customer number in the Z table and the SOLD_TO in the infocube.

How can I fix this problem?  Modifying the z table?

Thanks in advance.

Regards.