Help with my App Store updates

Question

i have macbook pro for a year now and from the moment i bought it i cant update any of my purchases. it used to wrote error 100 and now error 20. please help. thank you, tal

Answer 1

If you have more than one user account, these instructions must be carried out as an administrator.
Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Console in the icon grid.
Select "/var/log/install.log" from the file list on the left. If you don't see that list, select
View ▹ Show Log List
from the menu bar. Then select the messages from the last installation or update attempt, starting from the time when you initiated it. If you're not sure when that was, start over and note the time. Copy them to the Clipboard (command-C). Paste into a reply to this message (command-V).
If there are runs of repeated messages, post only one example of each. Don’t post many repetitions of the same message.
When posting a log extract, be selective. Don't post more than is requested.
Please do not indiscriminately dump thousands of lines from the log into this discussion.
Important: Some private information, such as your name, may appear in the log. Edit it out by search-and-replace in a text editor before posting.