One reason could be that the member's loan account is not actually attached to the category for which you increased the disbursement limit.  Here's the usual procedure for increasing a limit when the category also needs to be adjusted:
  1. First verify the correct loan category code by viewing the Visa loan account in Member Account Inquiry.
  2. If the member's disbursement limit needs to be greater than the category will allow, you first need to launch Tool #458 "Loan Category Configuration" and select the category you noted on the previous step.  On the second screen, adjust the disbursement limit for that loan category as appropriate.
  3. Next, launch Tool #20 "Update Acocunt Information" (shortcut: acct), enter the member's account number and increase the disbursement limit for this member.