How to fix "Mounting Failed" message when installing

Question

Everytime I try to download and install a program (like Opera or Google Chrome) the installation stops and a msg appears in my download window saying "Mounting Failed" What is this? PLease help.I have Intel iMac, 10.6, Flashplayer 11.2. I'm trying to install and use another browser, because I'm also having trouble watching things like Netflix, You Tube, Hulu Plus, etc. Thank you:(

Answer 1

The validation result is that the signature is invalid. The following is abstracted from XMLSignatureValidator - Adobe ActionScript® 3 (AS3 ) API Reference. It would be helpful for you to understand the validation result.
About signature status:
The validity of an XML signature can be valid, invalid, or unknown. The overall status depends on the verification status of the individual components of the signature file:
digestStatus — The validity of the cryptographic of the signature computed over the SignedInfo element. Can be valid, invalid, or unknown.
identityStatus — The validity of the signing certificate. If the certificate has expired, has been revoked, or altered, the status is invalid. If the certificate cannot be chained to a trusted root certificate, the status is unknown. The certificate is not checked if the digest is invalid. If not checked, the status will be reported as unknown.
referencesStatus — The validity of the data addressed by the references in the SignedInfo element of the signature file. Can be valid, invalid, or unknown. The references are not checked if the digest or certificate is invalid. Reference checking can also be skipped based on the setting of the referencesValidationSetting property. If not checked, the status will be reported as unknown.
The signature validity reported by the validityStatus property can be:
valid — If referencesStatus, digestStatus, and identityStatus are all valid.
invalid — If any individual status is invalid.
unknown — If referencesStatus,  digestStatus, or identityStatus is unknown.