DTS Package Error: Login failed for user sa

I am trying to edit a DTS package which is a transfer of data between two tables (connections)

i can view the properties of either connection but i get this error when i try to edit the transformation section of a pakcage that is supposed to transfer data from one table to another.

Login failed for user 'sa'

i am running enterprise manager on the server itself so i shouldn't have any connection issues.

if i try to change the authentication on either connection from "use SQL authentication" to "use windows NT authentication" i get this error:

' Cannot generate SSPI context 'Note: There are too many unknowns here to intelligently troubleshoot the situation:

S1 [I am trying to edit a DTS package which is a transfer of data between two tables (connections)]
Q1 Are both tables on the same server or on different servers?

S2 [i can view the properties of either connection but i get this error when i try to edit the transformation section of a pakcage that is supposed to transfer data from one table to another.
Login failed for user 'sa' i am running enterprise manager on the server itself so i shouldn't have any connection issues.]
Q2 i Have you tried entering the login password for sa
ii What is the result then?
iii Can you sucessfully login using say, Query Analyzer as sa?

S3 if i try to change the authentication on either connection from "use SQL authentication" to "use windows NT authentication" i get this error:' Cannot generate SSPI context '
Q3 Are your Sql Server(s) set to use integrated, standard, mixed, etc. authentication?