Error when loading SSIS package

Hi all,

I have problem with SSIS. When I open my packages, I always get an error message which says like this:
There were errors while the package was being loaded.
The package might be corrupted.
See the Error List for details.

And, in error list, I get this error message:
Error loading DIM_BUSINESS_TYPES.dtsx: SSIS Error Code DTS_E_OLEDBERROR.  An OLE DB error has occurred. Error code: 0x80040E4D.  An OLE DB record is available.  Source: "Microsoft SQL Native Client"  Hresult: 0x80040E4D  Description: "Login failed for user 'user'.".

But the package itself seems doesnt have any errors at all. When I try to run the package, it runs fine.
Btw, I use package configuration which is stored in sql server table, including the password for connectionstring.

So, what's actually wrong with my package?

Thanks