I went to the Reasons to Believe website and searched their articles with the keywords "endogenous retroviruses". From what I can see, they all discuss the same misinformation already covered earlier in this thread.
You searched for endogenous retroviruses - Reasons to Believe
1. Retroviral insertion is not random enough. That's false. Even in a best case scenario, insertional bias will only produce ~1% shared ERV's.
2. ERV's have function. Only a tiny fraction can be shown to have function, and even if they all had function they would still be smoking gun evidence for common ancestry.
3. PtERV1 is found in chimps and gorillas but not humans or orangutans. They forget to mention that they are not at orthologous positions in the chimp and gorilla genomes.
4. Departures from the expected phylogeny. There are known mechanisms that create these departures, such as ILS. It is expected that we will see a noisy phylogenetic signal if species evolved from a common ancestor. It is the ratio of noise to signal that matters, and they are reticent to even acknowledge the massive and overwhelming phylogenetic signal that sits out way above the noise.
5. Retroviruses can't produce ERVs in the first place. They acknowledge the case of ERVs being produced by an exogenous retrovirus in koalas, but they tell their audience to just ignore it for no apparent reason.
Nothing really original here. Just a rehash of what other creationist authors have written.