If she is from a visa exempted country then she wont have a problem. The temporary travel certificate is when you don't have a PR card but you have been granted the PR and you want to come back into the country.
"The Travel Document - Permanent Resident Abroad program issues temporary travel documents to permanent residents of Canada abroad who do not have a permanent resident card (PR Card)."
http://www.servicecanada.gc.ca/eng/goc/travel_document_pr.shtml
IF she is from the Visa excepted country then it wont be a problem
"If you are a citizen of a country where you do not require a visa to visit Canada, you must still:
show an immigration officer that you satisfy all other requirements to enter Canada. If you do not, you may not be allowed to enter.
have a valid passport. Some citizens from visa‑exempt countries have to meet more requirements, such as having a machine-readable passport or an e‑passport to travel to Canada. Find out what the specific information on passport requirements are for your country.
find out if you need to undergo a medical examination. Visit a visa office to receive instructions on undergoing a medical examination."
http://www.cic.gc.ca/english/visit/visa-exempt.asp
http://www.cic.gc.ca/english/visit/apply-who.asp