When Betty Heslop writes the first check to "cash" for Muriel to buy cosmetics, it is dated 12-1-1994. When Muriel hands her father a check for $5,000 near the end of the film, that check is dated 2-11-1992.
While Muriel and Rhonda are imitating ABBA on stage, Tania and Nicole get into a knockdown fight and the entire table is disrupted. When we cut back to Muriel and Rhonda, the girls still sitting there just watching. We can see the backs of their heads, and their dates are standing enjoying the show as before.
David's last name is listed in the credits as Van Arkle (no "c"). The same error is made in the subtitles for the Australian DVD.
The taxi the main characters enter near the end of the movie has white exterior door handles. During the same ride, the taxi has black door handles.
When Brice is on top of Muriel on the sofa, Muriel's arm changes from by her head, to gripping Brice's arm.
The backyard grass was still smoldering days after the fire.
When Muriel hands her father a check at the end of the film, you can see it's for $5,000. She says, "That's not all of it..." and in fact it isn't, because the amount was established earlier as $12,000.
When Muriel's mother writes a check and gives it to Muriel, the year marked is 1994. Later in the film, when Muriel writes a check and gives it to her father, the year marked is 1992.
In Muriel's Singles Magazine, there is a half-page profile on the 'bachelor of the month', Graham (36y/o). His image is then used a few pages later for a different man who is 32y/o and lives in Maroubra .
South Africa was banned from the Olympic Games in 1960 due to apartheid, but reinstated in 1992 and participated in the Barcelona games. David should be able to compete for his home country and not need to immigrate to Australia; however, it is possible that he or his coach believed another ban might be imminent and planned accordingly.
When Muriel is trying on a wedding dress in the shop, and is admiring it in the full-length mirror, to the right in the mirror, you can clearly see a crewmember standing there, before quickly darting out of the reflection.
David's coach describes South Africa as being in a state of "civil war". The early nineties were marked by unrest, including terrorist attacks and retaliation by the government; however, the violence is not generally regarded as having risen to the severity or organization of civil warfare.