The SELECT permission was denied on the object 'syscolumns', database 'mssqlsystemresource', schema 'sys'
As the error indicates the login does not have SELECT permissions on the sys schema. This would require you to specifically grant SELECT to the login, or I believe you could also just GRANT VIEW DEFINITION for the database.

Update
Sorry just caught that last sentence. I have not worked with that software but seems it might be using a different login to execute the query if you can execute the same query fine in SSMS.

On a side note, since you are in SQL 2005, it would be a better practice to start using the new views for looking at catalog information.